Add architecture to the README

README.md

@@ -33,3 +33,23 @@ xhost +
 # Run the clock
 sudo ./.venv/bin/python3 main.py
 ```
+
+## Architecture
+The main system running the software is a Raspberry Pi Zero 2 W. The display is a 240x240 pixel SPI display.
+
+In terms of software stack:
+- The clock's software is written in Python, using the Pygame library for rendering the display.
+- The software is multithreaded:
+  - One thread for the display, which renders the display (with pygame).
+  - One thread for the LEDs, controlling the patterns (with either neopixel or dummy led libraries).
+  - One thread for the web server, which serves the configuration page and API endpoints.
+  - The main thread controls the other threads and handles changes to the configuration.
+- Wayland is used as the display server, as it is faster than X11 and works well with the SPI display.
+- For operating system we use Raspberry Pi OS Lite, with Wayland and the necessary dependencies installed.
+
+It's designed to be:
+- Modular, with different modules - both widgets for the display and patterns for the LEDs that 
+  can be added or removed. The clock can be configured to display different modules in different orders, 
+  and the modules can be easily created or modified.
+- Easily extensible, with a simple API for creating new modules. The clock is also designed to be 
+  easily configurable, with a simple configuration file that can be edited to change the appearance of the clock.