I decided to make a powerful 8-bit basic computer using Arduino. The computer is running fully functional port of MS Basic OS called TinyBasic Plus. I rewrote the whole OS to fit my needs, I'll include the sketch shortly. The computer is measuring just 9,5x9,5x4 cm! On the left side of the computer is a CANNON25 connector. This connector is a GPIO port, which you can control using custom commands that enable you to control external hardware, like LED strips, RTCs, UART devices and much more. The main MCU is ATMEGA1284P, and the ATMEGA328P is acting as a graphical coprocessor, taking care of displaying text, bitmaps, simple vector graphics and controlling brightness of display. I decided to use Monochrome 128x64 LCD display as a output device. It's not ideal, but it's cheap :). These two MCUs are connected using Serial UART. I've used SD Card as a place to save your Basic programs. As a input device I used a standard PS/2 keyboard.