Simulate a quantum computer with an Arduino, possible sort of.
two leds (one off one on) can simulate superposition of a binary state. The leds blink at high speed .
5 leds (different PWM levels) can simulate a 5 state-system. The PWM levels rotate randomly.
you can simulate that a quantum system comes to a solution (quantum collapse) by suddenly stopping the blinking or rotating.
Other more complex quantum computing states might need more (perhaps even a MEGA or DUE 