Dirty semaphore to play with.
It's written for a ATMEGA168p but can be easily ported to any microcontroller of the same family.
5v--- BTN-----> PIN4 (INT0)
|
150R
|
GND
GND---150R---|<RED ----> PIN11 (PD6)
GND---150R---|<YELLOW ----> PIN12 (PD7)
GND---150R---|<GREEN ----> PIN17 (PB0)
The microcontroller sleeps after a few sequences. The button allows the user to change the sequence.