This circuit is designed to drive an electronic 3x3x3 cube consisting of 27 LEDs. IC 4020 will drive the LED circuit as well as a 14-stage binary counter and uses 9 output pins. Each output from the IC can drive 3 white LEDs arranged in series.
A dropper resistor is not required in this circuit because LEDs only provide a maximum current of 15mA per output. IC 4020 in this series can produce 512 beautiful patterns on the LED light.