Create Christmas Light Effect With 3 LEDs, 3 Resistors, No External Power and Two Set of Effects. Circuit written in code.

It is quite easy. 

LED1 ---(+)---[200 Ohm Resister]---- Pin 8 LED2 ---(+)---[200 Ohm Resister]---- Pin 7 LED3 ---(+)------------------------- Pin 12 LED1, LED2, LED3 ----(-)----[10K Ohm Resister]--- GND