diff --git a/.gitignore b/.gitignore
index fed370c..cea6c0e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -2,3 +2,5 @@ error.glsl
 forge_default_save.txt
 build
 tmp*
+debug.png
+forge_default_save.txt.bck
diff --git a/2026-10-28_21-38.png b/2026-10-28_21-38.png
deleted file mode 100644
index 87256a4..0000000
Binary files a/2026-10-28_21-38.png and /dev/null differ
diff --git a/Makefile b/Makefile
index 881c2d5..6bd0d36 100644
--- a/Makefile
+++ b/Makefile
@@ -53,7 +53,7 @@ setup-services:
 
 .PHONY: setup-bashrc
 setup-bashrc:
-	$(PROJECT_DIR)/line_in_file.sh "make -C $(PROJECT_DIR) --no-print-directory start" "$(HOME)/.bashrc"
+	$(PROJECT_DIR)/scripts/line_in_file.sh "make -C $(PROJECT_DIR) --no-print-directory start" "$(HOME)/.bashrc"
 
 .PHONY: install
 install: remove-passwd apt-install pip-install setup-weston remove-motd disable-cloud-init setup-services setup-bashrc
@@ -71,7 +71,7 @@ run: $(BUILD_DIR)/$(TARGET)
 
 .PHONY: start-bg
 start-bg:
-	@python3 $(PROJECT_DIR)/i2c.py >> $(PROJECT_DIR)/python.log&
+	@python3 $(PROJECT_DIR)/__main__.py &> $(PROJECT_DIR)/python.log &
 
 .PHONY: start-fg
 start-fg:
diff --git a/__main__.py b/__main__.py
new file mode 100755
index 0000000..7a95cc1
--- /dev/null
+++ b/__main__.py
@@ -0,0 +1,6 @@
+#!/usr/bin/env python3
+
+from src.forge_invar import main
+
+if __name__ == "__main__":
+    main()
diff --git a/host_generate.py b/host_generate.py
deleted file mode 100644
index 007b0b0..0000000
--- a/host_generate.py
+++ /dev/null
@@ -1,106 +0,0 @@
-from PIL import Image, ImageDraw, ImageFont, ImageMath
-
-# TODO clean
-
-font = ImageFont.truetype("./TinyAndChunkyRegular.ttf", 5)
-font2 = ImageFont.truetype("./Px437_IBM_BIOS.ttf", 8)
-
-im0 = Image.new("1", (128, 64), "black")
-
-draw = ImageDraw.Draw(im0)
-
-draw.text((26, 24), "F.O.R.G.E.", fill="white", font=font2)
-draw.rectangle((24, 35, 104, 40), outline="white", fill="black")
-
-im0.save("i2c_loading.png")
-
-im = Image.new("1", (128, 64), "black")
-
-draw = ImageDraw.Draw(im)
-
-
-# tempo
-draw.text((7, -2), "TEMPO:", fill="white", font=font)
-draw.rectangle((6, 6, 60, 11), outline="white", fill="black")
-
-# time
-draw.text((68, -2), "TIME:", fill="white", font=font)
-draw.rectangle((67, 6, 121, 11), outline="white", fill="black")
-
-# pipes
-draw.rectangle((26, 22, 78, 24), fill="white")
-draw.rectangle((26, 46, 78, 48), fill="white")
-draw.rectangle((78, 34, 128, 36), fill="white")
-draw.rectangle((76, 23, 78, 46), fill="white")
-
-# squares
-draw.rectangle((12, 16, 26, 30), outline="white", fill="black")
-draw.rectangle((41, 16, 55, 30), outline="white", fill="black")
-
-draw.rectangle((12, 40, 26, 54), outline="white", fill="black")
-draw.rectangle((41, 40, 55, 54), outline="white", fill="black")
-
-draw.rectangle((70, 28, 84, 42), outline="white", fill="black")
-draw.rectangle((99, 28, 113, 42), outline="white", fill="black")
-
-selected_bounds = [
-    (10, 14, 28, 32),
-    (10, 38, 28, 56),
-    (39, 14, 57, 32),
-    (39, 38, 57, 56),
-    (0, 0, 0, 0),
-    (97, 26, 115, 44),
-]
-
-# page
-draw.circle((55, 61), 2, outline="white", fill="black")
-draw.circle((63, 61), 2, outline="white", fill="black")
-draw.circle((71, 61), 2, outline="white", fill="black")
-
-im.save("i2c_background.png")
-
-# ---
-
-# tempo
-draw.text((42, -2), "240", fill="white", font=font)
-draw.rectangle((6, 7, 6 + 53 * 1, 10), fill="white", width=0)
-
-# time
-draw.text((94, -2), "1234", fill="white", font=font)
-draw.rectangle((67, 7, 67 + 53 * 1, 10), fill="white", width=0)
-
-draw.circle((55, 61), 2, fill="white")
-
-# selected
-
-for i in range(len(selected_bounds)):
-    if selected_bounds[i][0] > 0:
-        draw.rectangle(selected_bounds[i], outline="white", fill=None)
-
-im_overlay = Image.new("1", (128, 64), "black")
-draw2 = ImageDraw.Draw(im_overlay)
-
-
-# shaders
-draw2.text((16, 20), "0", fill="white", font=font2)
-draw2.text((45, 20), "2", fill="white", font=font2)
-draw2.text((16, 44), "1", fill="white", font=font2)
-draw2.text((45, 44), "3", fill="white", font=font2)
-draw2.text((74, 32), "K", fill="white", font=font2)
-draw2.text((103, 32), "6", fill="white", font=font2)
-
-im = ImageMath.lambda_eval(lambda args: args["convert"](args["a"] ^ args["b"], "1"), a=im, b=im_overlay)
-
-# ---
-
-im = im.resize((1280, 640)).convert("RGB")
-
-draw2 = ImageDraw.Draw(im)
-
-for x in range(1, 128):
-    draw2.line((x * 10, 0, x * 10, 640), fill=(50, 50, 50))
-for y in range(1, 64):
-    draw2.line((0, y * 10, 1280, y * 10), fill=(50, 50, 50))
-
-
-im.resize((1280, 640)).save("tmp.png")
diff --git a/i2c.py b/i2c.py
deleted file mode 100755
index bbb612d..0000000
--- a/i2c.py
+++ /dev/null
@@ -1,190 +0,0 @@
-#!/usr/bin/env python3
-
-# see https://electricalflux.com/mcu-raspberry/i2c-oled-display-raspberry-pi-5-wiring-code
-
-import collections
-import pathlib
-import sys
-import time
-
-from luma.core.error import DeviceNotFoundError
-from luma.core.interface.serial import i2c
-from luma.oled.device import device, sh1106
-from PIL import Image, ImageDraw, ImageFont, ImageMath
-
-TARGET_FILE = pathlib.Path(__file__).parent / "forge_default_save.txt"
-TARGET_FILE_BACKUP = pathlib.Path(__file__).parent / "forge_default_save.txt.bck"
-
-ESTIMATED_BOOT_TIME_SECONDS = 18.0
-
-data: dict[str, float] = collections.defaultdict(lambda: 0)
-
-font1 = ImageFont.truetype("./TinyAndChunkyRegular.ttf", 5)
-font2 = ImageFont.truetype("./Px437_IBM_BIOS.ttf", 8)
-loading_img = Image.open("i2c_loading.png").convert("1")
-background_img = Image.open("i2c_background.png").convert("1")
-blank_im = Image.new("1", (128, 64), "black")
-
-selected_bounds = [
-    (10, 14, 28, 32),
-    (10, 38, 28, 56),
-    (39, 14, 57, 32),
-    (39, 38, 57, 56),
-    (0, 0, 0, 0),
-    (97, 26, 115, 44),
-]
-
-
-def try_restore_backup() -> bool:
-    if TARGET_FILE_BACKUP.exists() and readfile(TARGET_FILE_BACKUP):
-        TARGET_FILE.write_text(TARGET_FILE_BACKUP.read_text())
-        return True
-    return False
-
-
-def readfile(file: pathlib.Path = TARGET_FILE) -> bool:
-    try:
-        content = file.read_text()
-    except:  # noqa: E722
-        return False
-    for line in content.splitlines():
-        key, value = line.split("=", maxsplit=2)
-        data[key] = float(value)
-    if "time" in data:
-        TARGET_FILE_BACKUP.write_text(content)
-    return "time" in data
-
-
-def open_device() -> device:
-    # Pin definitions: I2C Bus 1 (SDA=GPIO2, SCL=GPIO3)
-    # Default SSD1306 I2C address is 0x3C
-    serial_interface = i2c(port=1, address=0x3C)
-
-    try:
-        # Initialize the device. If using SH1106, change ssd1306 to sh1106
-        return sh1106(serial_interface, width=128, height=64, rotate=2)
-    except DeviceNotFoundError:
-        print("Fatal: OLED not found at 0x3C. Check wiring and run i2cdetect -y 1")
-        sys.exit(1)
-    except OSError as e:
-        if e.errno == 121:
-            print(
-                "Fatal: Remote I/O error. I2C bus is locked or physically disconnected."
-            )
-        else:
-            print(f"Fatal OS Error: {e}")
-        sys.exit(1)
-
-
-def print_loading(restored: bool, t0: float) -> Image.Image:
-    im = loading_img.copy()
-    draw = ImageDraw.Draw(im)
-
-    now = time.time()
-
-    percent = min(1.0, (now - t0) / ESTIMATED_BOOT_TIME_SECONDS)
-
-    draw.rectangle((24, 35, 24 + 80 * percent, 40), fill="white")
-
-    if not restored:
-        draw.circle((4, 4), 1, fill="white")
-
-    return im
-
-
-def print_monitor() -> Image.Image:
-    im = background_img.copy()
-    draw = ImageDraw.Draw(im)
-
-    im_overlay = blank_im.copy()
-    draw2 = ImageDraw.Draw(im_overlay)
-
-    # tempo
-    draw.text((42, -2), f"{int(data['tempo'])}", fill="white", font=font1)
-    draw.rectangle(
-        (6, 7, 6 + 53 * (data["beats"] - int(data["beats"])), 10), fill="white", width=0
-    )
-
-    # time
-    draw.text((94, -2), f"{int(data['time'])}", fill="white", font=font1)
-    draw.rectangle(
-        (67, 7, 67 + 53 * (data["time"] - int(data["time"])), 10), fill="white", width=0
-    )
-
-    # page
-    draw.circle((55 + 8 * int(data["page"]), 61), 2, fill="white")
-
-    # selected
-    selected = int(data["selected"])
-    draw.rectangle(selected_bounds[selected], outline="white", fill=None)
-
-    # TODO active fx/src
-
-    # fx/mix values
-    # todo random and time based
-    fxa_value = 1 - data['value_18_x'] / 127
-    draw.rectangle((41, 16 + round(14 * fxa_value), 55, 30), fill="white")
-    fxb_value = 1 - data['value_25_x'] / 127
-    draw.rectangle((41, 40 + round(14 * fxb_value), 55, 54), fill="white")
-    mfx_value = 1 - data['value_32_x'] / 127
-    draw.rectangle((99, 28 + round(14 * mfx_value), 113, 42), fill="white")
-    mix_value = 1 - data['value_34_x'] / 127
-    draw.rectangle((70, 28 + round(14 * mix_value), 84, 42), fill="white")
-
-    # active shaders
-    draw2.text((16, 20), hex(int(data["state_0"]))[2].upper(), fill="white", font=font2)
-    draw2.text((16, 44), hex(int(data["state_1"]))[2].upper(), fill="white", font=font2)
-    draw2.text((45, 20), hex(int(data["state_2"]))[2].upper(), fill="white", font=font2)
-    draw2.text((45, 44), hex(int(data["state_3"]))[2].upper(), fill="white", font=font2)
-    draw2.text(
-        (103, 32), hex(int(data["state_6"]))[2].upper(), fill="white", font=font2
-    )
-    mix_type = data['value_33_x'] == 0
-    draw2.text((74, 32), "M" if mix_type else "K", fill="white", font=font2) # TODO
-
-    return ImageMath.lambda_eval(lambda args: args["convert"](args["a"] ^ args["b"], "1"), a=im, b=im_overlay)
-
-
-def main():
-    restored = try_restore_backup() or readfile()
-
-    device = open_device()
-
-    initial = True
-    started = False
-
-    t0 = time.time()
-
-    try:
-        device.display(print_loading(restored, t0))
-
-        while True:
-            if not readfile():
-                time.sleep(0.01)
-                continue
-
-            if initial or started:
-                if not started:
-                    started = "time" in data and data["time"] == 0
-                    if started:
-                        initial = False
-                device.display(print_loading(restored, t0))
-            else:
-                device.display(print_monitor())
-
-            if started and data["time"] > 0:
-                initial = False
-                started = False
-    except KeyboardInterrupt:
-        print("Exiting gracefully...")
-    except OSError as e:
-        if e.errno == 121:
-            print("Runtime Error: I2C bus dropped. Check physical connections.")
-        device.cleanup()
-        sys.exit(1)
-    finally:
-        device.cleanup()
-
-
-if __name__ == "__main__":
-    main()
diff --git a/pyproject.toml b/pyproject.toml
index 70e8895..4625127 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,11 +1,23 @@
 [project]
 name = "forge-invar"
-version = "0.0.0"
+version = "0.1.0"
+description = "FORGE invar background process for Raspberry Pi"
+readme = "README.md"
+authors = [
+    { name = "klemek", email = "klemek.dev@proton.me" }
+]
 requires-python = ">=3.14"
 dependencies = [
     "luma-oled>=3.16.0",
 ]
 
+[project.scripts]
+forge-invar = "forge_invar:main"
+
+[build-system]
+requires = ["uv_build>=0.13.0,<0.14.0"]
+build-backend = "uv_build"
+
 [dependency-groups]
 dev = [
     "ruff>=0.17.3",
diff --git a/Px437_IBM_BIOS.ttf b/resources/Px437_IBM_BIOS.ttf
similarity index 100%
rename from Px437_IBM_BIOS.ttf
rename to resources/Px437_IBM_BIOS.ttf
diff --git a/TinyAndChunkyRegular.ttf b/resources/TinyAndChunkyRegular.ttf
similarity index 100%
rename from TinyAndChunkyRegular.ttf
rename to resources/TinyAndChunkyRegular.ttf
diff --git a/i2c_background.png b/resources/background.png
similarity index 100%
rename from i2c_background.png
rename to resources/background.png
diff --git a/i2c_loading.png b/resources/loading.png
similarity index 100%
rename from i2c_loading.png
rename to resources/loading.png
diff --git a/resources/mock_data.txt b/resources/mock_data.txt
new file mode 100644
index 0000000..69e0dd7
--- /dev/null
+++ b/resources/mock_data.txt
@@ -0,0 +1,130 @@
+time=226.380635
+beats=175.725006
+demo=0
+auto_random=0
+auto_random_cycle=4
+tempo=60
+page=0
+selected=0
+seed_0=898
+state_0=0
+seed_1=472
+state_1=9
+seed_2=243
+state_2=3
+seed_3=547
+state_3=14
+seed_4=524
+state_4=13
+seed_5=251
+state_5=10
+seed_6=808
+state_6=4
+active_0=0
+active_1=0
+active_2=0
+value_0_x=127
+value_0_y=0
+value_0_z=0
+value_1_x=111
+value_1_y=100
+value_1_z=71
+value_2_x=0
+value_2_y=127
+value_2_z=127
+value_3_x=56
+value_3_y=19
+value_3_z=71
+value_4_x=0
+value_4_y=0
+value_4_z=127
+value_5_x=38
+value_5_y=116
+value_5_z=82
+value_6_x=127
+value_6_y=127
+value_6_z=127
+value_7_x=32
+value_7_y=114
+value_7_z=113
+value_8_x=127
+value_8_y=0
+value_8_z=127
+value_9_x=83
+value_9_y=93
+value_9_z=62
+value_10_x=127
+value_10_y=127
+value_10_z=0
+value_11_x=92
+value_11_y=121
+value_11_z=1
+value_12_x=0
+value_12_y=127
+value_12_z=127
+value_13_x=20
+value_13_y=105
+value_13_z=64
+value_14_x=127
+value_14_y=0
+value_14_z=127
+value_15_x=78
+value_15_y=115
+value_15_z=28
+value_16_x=127
+value_16_y=127
+value_16_z=127
+value_17_x=89
+value_17_y=114
+value_17_z=115
+value_18_x=22
+value_18_y=112
+value_18_z=0
+value_19_x=0
+value_19_y=0
+value_19_z=127
+value_20_x=33
+value_20_y=102
+value_20_z=121
+value_21_x=0
+value_21_y=0
+value_21_z=127
+value_22_x=34
+value_22_y=117
+value_22_z=92
+value_23_x=127
+value_23_y=127
+value_23_z=127
+value_24_x=24
+value_24_y=1
+value_24_z=103
+value_25_x=62
+value_25_y=43
+value_25_z=127
+value_26_x=127
+value_26_y=127
+value_26_z=127
+value_27_x=62
+value_27_y=28
+value_27_z=88
+value_28_x=127
+value_28_y=0
+value_28_z=127
+value_29_x=76
+value_29_y=64
+value_29_z=8
+value_30_x=127
+value_30_y=0
+value_30_z=0
+value_31_x=74
+value_31_y=76
+value_31_z=10
+value_32_x=11
+value_32_y=67
+value_32_z=0
+value_33_x=127
+value_33_y=0
+value_33_z=0
+value_34_x=103
+value_34_y=57
+value_34_z=0
diff --git a/append_to_file.sh b/scripts/append_to_file.sh
similarity index 100%
rename from append_to_file.sh
rename to scripts/append_to_file.sh
diff --git a/line_in_file.sh b/scripts/line_in_file.sh
similarity index 100%
rename from line_in_file.sh
rename to scripts/line_in_file.sh
diff --git a/src/forge_invar/__init__.py b/src/forge_invar/__init__.py
new file mode 100644
index 0000000..3db892f
--- /dev/null
+++ b/src/forge_invar/__init__.py
@@ -0,0 +1,40 @@
+import argparse
+import time
+
+from .display import (
+    debug_image,
+    generate_background_image,
+    generate_loading_image,
+    get_display,
+)
+from .forge_data import ForgeData
+from .i2c import I2C
+
+
+def host_generate() -> None:
+    data = ForgeData().mock()
+    generate_loading_image()
+    generate_background_image()
+    image = get_display(data, 0)
+    debug_image(image)
+
+
+def main() -> None:
+    parser = argparse.ArgumentParser()
+    parser.add_argument("--generate", action="store_true")
+    args = parser.parse_args()
+
+    if args.generate:
+        host_generate()
+        return
+
+    t0 = time.time()
+    with ForgeData() as data, I2C() as device:
+        device.update_display(get_display(data, t0))
+
+        while True:
+            if not data.update():
+                time.sleep(0.01)
+                continue
+
+            device.update_display(get_display(data, t0))
diff --git a/src/forge_invar/constants.py b/src/forge_invar/constants.py
new file mode 100644
index 0000000..c552bec
--- /dev/null
+++ b/src/forge_invar/constants.py
@@ -0,0 +1,37 @@
+import pathlib
+
+PROJECT_PATH = pathlib.Path(__file__).parent.parent.parent
+RESOURCES_PATH = PROJECT_PATH / "resources"
+
+FORGE_SAVE_PATH = PROJECT_PATH / "forge_default_save.txt"
+FORGE_SAVE_BACKUP_PATH = PROJECT_PATH / "forge_default_save.txt.bck"
+MOCK_SAVE_PATH = RESOURCES_PATH / "mock_data.txt"
+
+
+FONT_1_PATH = RESOURCES_PATH / "TinyAndChunkyRegular.ttf"
+FONT_2_PATH = RESOURCES_PATH / "Px437_IBM_BIOS.ttf"
+
+LOADING_IMG_PATH = RESOURCES_PATH / "loading.png"
+BACKGROUND_IMG_PATH = RESOURCES_PATH / "background.png"
+
+ESTIMATED_BOOT_TIME_SECONDS = 18.0
+
+SELECTED_RECT_BOUNDS = [
+    (10, 14, 28, 32),
+    (10, 38, 28, 56),
+    (39, 14, 57, 32),
+    (39, 38, 57, 56),
+    (0, 0, 0, 0),
+    (97, 26, 115, 44),
+]
+
+ACTIVE_SRC_RECT_BOUNDS = [
+    (10, 32, 28, 32),
+    (10, 56, 28, 56),
+]
+
+ACTIVE_FX_RECT_BOUNDS = [
+    (39, 32, 57, 32),
+    (39, 56, 57, 56),
+    (97, 44, 115, 44),
+]
diff --git a/src/forge_invar/display.py b/src/forge_invar/display.py
new file mode 100644
index 0000000..7545608
--- /dev/null
+++ b/src/forge_invar/display.py
@@ -0,0 +1,167 @@
+import time
+
+from PIL import Image, ImageDraw, ImageFont, ImageMath
+
+from .constants import (
+    ACTIVE_FX_RECT_BOUNDS,
+    ACTIVE_SRC_RECT_BOUNDS,
+    BACKGROUND_IMG_PATH,
+    ESTIMATED_BOOT_TIME_SECONDS,
+    FONT_1_PATH,
+    FONT_2_PATH,
+    LOADING_IMG_PATH,
+    SELECTED_RECT_BOUNDS,
+)
+from .enums import ForgeState
+from .forge_data import ForgeData
+
+FONT_1 = ImageFont.truetype(FONT_1_PATH, 5)
+FONT_2 = ImageFont.truetype(FONT_2_PATH, 8)
+LOADING_IMG = Image.open(LOADING_IMG_PATH)
+BACKGROUND_IMG = Image.open(BACKGROUND_IMG_PATH)
+BLANK_IMG = Image.new("1", (128, 64), "black")
+
+
+def __xor(img1: Image.Image, img2: Image.Image) -> Image.Image:
+    return ImageMath.lambda_eval(
+        lambda args: args["convert"](args["a"] ^ args["b"], "1"), a=img1, b=img2
+    )
+
+
+def __get_loading_display(data: ForgeData, t0: float) -> Image.Image:
+    im = LOADING_IMG.copy()
+    draw = ImageDraw.Draw(im)
+
+    now = time.time()
+
+    percent = min(1.0, (now - t0) / ESTIMATED_BOOT_TIME_SECONDS)
+
+    draw.rectangle((24, 35, 24 + 80 * percent, 40), fill="white")
+
+    if data.state == ForgeState.INITIAL:
+        draw.circle((4, 4), 1, fill="white")
+
+    return im
+
+
+def __get_running_display(data: ForgeData) -> Image.Image:
+    im = BACKGROUND_IMG.copy()
+    draw = ImageDraw.Draw(im)
+
+    im_overlay = BLANK_IMG.copy()
+    draw2 = ImageDraw.Draw(im_overlay)
+
+    # tempo
+    draw.text((42, -2), f"{int(data.tempo)}", fill="white", font=FONT_1)
+    draw.rectangle((6, 7, 6 + int(53 * data.beat_progress), 10), fill="white", width=0)
+
+    # time
+    draw.text((94, -2), f"{int(data.time)}", fill="white", font=FONT_1)
+    draw.rectangle(
+        (67, 7, 67 + int(53 * data.time_progress), 10), fill="white", width=0
+    )
+
+    # page
+    draw.circle((55 + 8 * data.page, 61), 2, fill="white")
+
+    # selected
+    draw.rectangle(SELECTED_RECT_BOUNDS[data.selected], outline="white", fill=None)
+
+    # active
+    draw.rectangle(ACTIVE_SRC_RECT_BOUNDS[data.active(0)], fill="white")
+    draw.rectangle(ACTIVE_FX_RECT_BOUNDS[data.active(1)], fill="white")
+
+    # fx/mix values
+    draw.rectangle((41, 16 + round(14 * (1 - data.fxa_value)), 55, 30), fill="white")
+    draw.rectangle((41, 40 + round(14 * (1 - data.fxb_value)), 55, 54), fill="white")
+    draw.rectangle((99, 28 + round(14 * (1 - data.mfx_value)), 113, 42), fill="white")
+    draw.rectangle((70, 28 + round(14 * (1 - data.mix_value)), 84, 42), fill="white")
+
+    # active shaders
+    draw2.text((16, 20), hex(data.frag_state(0))[2].upper(), fill="white", font=FONT_2)
+    draw2.text((16, 44), hex(data.frag_state(1))[2].upper(), fill="white", font=FONT_2)
+    draw2.text((45, 20), hex(data.frag_state(2))[2].upper(), fill="white", font=FONT_2)
+    draw2.text((45, 44), hex(data.frag_state(3))[2].upper(), fill="white", font=FONT_2)
+    draw2.text((103, 32), hex(data.frag_state(5))[2].upper(), fill="white", font=FONT_2)
+    # TODO print when random
+
+    draw2.text((74, 32), "K" if data.mix_mode_key else "M", fill="white", font=FONT_2)
+
+    # TODO show feedback
+
+    return __xor(im, im_overlay)
+
+
+def get_display(data: ForgeData, t0: float) -> Image.Image:
+    if data.state == ForgeState.RUNNING:
+        return __get_running_display(data)
+    return __get_loading_display(data, t0)
+
+
+def generate_loading_image() -> None:
+    global LOADING_IMG
+
+    im = BLANK_IMG.copy()
+
+    draw = ImageDraw.Draw(im)
+
+    draw.text((26, 24), "F.O.R.G.E.", fill="white", font=FONT_2)
+    draw.rectangle((24, 35, 104, 40), outline="white", fill="black")
+
+    im.save(LOADING_IMG_PATH)
+
+    LOADING_IMG = im
+
+
+def generate_background_image() -> None:
+    global BACKGROUND_IMG
+
+    im = BLANK_IMG.copy()
+
+    draw = ImageDraw.Draw(im)
+
+    # tempo
+    draw.text((7, -2), "TEMPO:", fill="white", font=FONT_1)
+    draw.rectangle((6, 6, 60, 11), outline="white", fill="black")
+
+    # time
+    draw.text((68, -2), "TIME:", fill="white", font=FONT_1)
+    draw.rectangle((67, 6, 121, 11), outline="white", fill="black")
+
+    # pipes
+    draw.rectangle((26, 22, 78, 24), fill="white")
+    draw.rectangle((26, 46, 78, 48), fill="white")
+    draw.rectangle((78, 34, 128, 36), fill="white")
+    draw.rectangle((76, 23, 78, 46), fill="white")
+
+    # squares
+    draw.rectangle((12, 16, 26, 30), outline="white", fill="black")
+    draw.rectangle((41, 16, 55, 30), outline="white", fill="black")
+
+    draw.rectangle((12, 40, 26, 54), outline="white", fill="black")
+    draw.rectangle((41, 40, 55, 54), outline="white", fill="black")
+
+    draw.rectangle((70, 28, 84, 42), outline="white", fill="black")
+    draw.rectangle((99, 28, 113, 42), outline="white", fill="black")
+
+    # page
+    draw.circle((55, 61), 2, outline="white", fill="black")
+    draw.circle((63, 61), 2, outline="white", fill="black")
+    draw.circle((71, 61), 2, outline="white", fill="black")
+
+    im.save(BACKGROUND_IMG_PATH)
+
+    BACKGROUND_IMG = im
+
+
+def debug_image(im: Image.Image) -> None:
+    im = im.resize((1280, 640)).convert("RGB")
+
+    draw2 = ImageDraw.Draw(im)
+
+    for x in range(1, 128):
+        draw2.line((x * 10, 0, x * 10, 640), fill=(50, 50, 50))
+    for y in range(1, 64):
+        draw2.line((0, y * 10, 1280, y * 10), fill=(50, 50, 50))
+
+    im.resize((1280, 640)).save("debug.png")
diff --git a/src/forge_invar/enums.py b/src/forge_invar/enums.py
new file mode 100644
index 0000000..da0f500
--- /dev/null
+++ b/src/forge_invar/enums.py
@@ -0,0 +1,8 @@
+import enum
+
+
+class ForgeState(enum.Enum):
+    INITIAL = enum.auto()
+    RESTORED = enum.auto()
+    STARTED = enum.auto()
+    RUNNING = enum.auto()
diff --git a/src/forge_invar/forge_data.py b/src/forge_invar/forge_data.py
new file mode 100644
index 0000000..da397cb
--- /dev/null
+++ b/src/forge_invar/forge_data.py
@@ -0,0 +1,132 @@
+import collections
+import pathlib
+import typing
+
+from .constants import FORGE_SAVE_BACKUP_PATH, FORGE_SAVE_PATH, MOCK_SAVE_PATH
+from .enums import ForgeState
+
+
+class ForgeRawData:
+    def __init__(self) -> None:
+        self.__data: dict[str, float] = collections.defaultdict(lambda: 0)
+
+    def try_restore_backup(self) -> bool:
+        if FORGE_SAVE_BACKUP_PATH.exists() and self.read(FORGE_SAVE_BACKUP_PATH):
+            FORGE_SAVE_PATH.write_text(FORGE_SAVE_BACKUP_PATH.read_text())
+            return True
+        return False
+
+    def read(self, file: pathlib.Path = FORGE_SAVE_PATH) -> bool:
+        try:
+            content = file.read_text()
+        except:  # noqa: E722
+            return False
+        for line in content.splitlines():
+            key, value = line.split("=", maxsplit=2)
+            self.__data[key] = float(value)
+        if "time" in self.__data:
+            FORGE_SAVE_BACKUP_PATH.write_text(content)
+            return True
+        return False
+
+    def __getitem__(self, key: str) -> float:
+        return self.__data[key]
+
+    def __contains__(self, key: str) -> bool:
+        return key in self.__data
+
+
+class ForgeData:
+    def __init__(self) -> None:
+        self.__data = ForgeRawData()
+        self.state = ForgeState.INITIAL
+
+    def __enter__(self) -> typing.Self:
+        if self.__data.try_restore_backup() or self.__data.read():
+            self.state = ForgeState.RESTORED
+        return self
+
+    def __exit__(self, *_) -> None:
+        pass
+
+    def __update_state(self) -> None:
+        if self.state == ForgeState.RUNNING:
+            return
+        elif self.state == ForgeState.STARTED:
+            if self.time > 0:
+                self.state = ForgeState.RUNNING
+        elif "time" in self.__data and self.time == 0:
+            self.state = ForgeState.STARTED
+
+    def update(self) -> bool:
+        if self.__data.read():
+            self.__update_state()
+            return True
+        return False
+
+    def value(self, n: int) -> tuple[float, float, float]:
+        return (
+            self.__data[f"value_{n}_x"] / 127,
+            self.__data[f"value_{n}_y"] / 127,
+            self.__data[f"value_{n}_z"] / 127,
+        )
+
+    def frag_state(self, n: int) -> int:
+        return int(self.__data[f"state_{n}"])
+
+    def active(self, n: int) -> int:
+        return int(self.__data[f"active_{n}"])
+
+    @property
+    def time(self) -> float:
+        return self.__data["time"]
+
+    @property
+    def time_progress(self) -> float:
+        return self.time - int(self.time)
+
+    @property
+    def tempo(self) -> float:
+        return self.__data["tempo"]
+
+    @property
+    def beats(self) -> float:
+        return self.__data["beats"]
+
+    @property
+    def beat_progress(self) -> float:
+        return self.beats - int(self.beats)
+
+    @property
+    def page(self) -> int:
+        return int(self.__data["page"])
+
+    @property
+    def selected(self) -> int:
+        return int(self.__data["selected"])
+
+    @property
+    def fxa_value(self) -> float:
+        # todo random and time based
+        return self.value(18)[0]
+
+    @property
+    def fxb_value(self) -> float:
+        return self.value(25)[0]
+
+    @property
+    def mfx_value(self) -> float:
+        return self.value(32)[0]
+
+    @property
+    def mix_value(self) -> float:
+        return self.value(34)[0]
+
+    @property
+    def mix_mode_key(self) -> bool:
+        return self.value(33)[0] > 0.
+
+    def mock(self) -> typing.Self:
+        self.__data.read(MOCK_SAVE_PATH)
+        self.state = ForgeState.RUNNING
+        return self
diff --git a/src/forge_invar/i2c.py b/src/forge_invar/i2c.py
new file mode 100644
index 0000000..c01f560
--- /dev/null
+++ b/src/forge_invar/i2c.py
@@ -0,0 +1,49 @@
+import sys
+import typing
+
+from luma.core.error import DeviceNotFoundError
+from luma.core.interface.serial import i2c
+from luma.oled.device import device, sh1106
+from PIL import Image
+
+
+class I2C:
+    def __init__(self) -> None:
+        self.__device: device | None = None
+
+    def __enter__(self) -> typing.Self:
+        self.__open_device()
+        return self
+
+    def __exit__(self, *_) -> None:
+        assert self.__device is not None
+        self.__device.cleanup()
+
+    def __open_device(self) -> None:
+        # Pin definitions: I2C Bus 1 (SDA=GPIO2, SCL=GPIO3)
+        # Default SSD1306 I2C address is 0x3C
+        serial_interface = i2c(port=1, address=0x3C)
+
+        try:
+            # Initialize the device. If using SH1106, change ssd1306 to sh1106
+            self.__device = sh1106(serial_interface, width=128, height=64, rotate=0)
+        except DeviceNotFoundError:
+            print("Fatal: OLED not found at 0x3C. Check wiring and run i2cdetect -y 1")
+            sys.exit(1)
+        except OSError as e:
+            if e.errno == 121:
+                print(
+                    "Fatal: Remote I/O error. I2C bus is locked or physically disconnected."
+                )
+            else:
+                print(f"Fatal OS Error: {e}")
+            sys.exit(1)
+
+    def update_display(self, image: Image.Image) -> None:
+        assert self.__device is not None
+        try:
+            self.__device.display(image)
+        except OSError as e:
+            if e.errno == 121:
+                print("Runtime Error: I2C bus dropped. Check physical connections.")
+            raise
diff --git a/uv.lock b/uv.lock
index 816593d..c966893 100644
--- a/uv.lock
+++ b/uv.lock
@@ -44,8 +44,8 @@ wheels = [
 
 [[package]]
 name = "forge-invar"
-version = "0.0.0"
-source = { virtual = "." }
+version = "0.1.0"
+source = { editable = "." }
 dependencies = [
     { name = "luma-oled" },
 ]