R1-R2-R3: 330Ω R4-R5-R6: 1MΩ C1-C2-C3: 1uF Q1-Q2-Q3: 2N7000 LED1-LED2-LED3: 5mm Red VCC: 3.3V/5V While playing with this ring oscillator circuit, you can define how fast you want the LEDs to sweep by ...

The ring oscillator cleverly produces three phase-shifted square waves such that a binary combination of the three phases offers six unique states.