This circuit drives a 3x3x3 cube consisting of 27 white LEDs. The 4020 IC is a
14 stage binary counter and we have used 9 outputs. Each output drives 3 white
LEDs in series and we have omitted a dropper resistor as the chip can only
deliver a maximum of 15mA per output. The 4020 produces 512 different patterns
before the sequence repeats and you have to build the project to see the effects
it produces on the 3D cube.