This is one of my previous projects that I worked on a while ago. This circuit makes the four LEDs flash clockwise. The knob on the right top is a potentiometer that adjusts the speed of the LEDs by adjusting the voltage and current at the Discharge and Threshold pin of the 555 timer IC (the small chip at the bottom). The bigger chip on the right bottom is a 4017 decade counter. Every time the clock input of the 4017 turns high, the chip sets the next output pin to high. It goes from 0 to 9 and keeps on repeating unless the reset pin is set to high. By connecting the reset pin to the fifth output (pin 10) I made it reset every four LEDs.
I got and modified this circuit from Bowden's Hobby Circuits. He has more projects on his main page.
Here is the schematic for this circuit.
