The matrix has seven columns, one for each segment on the display ... ve previously talked about [Fran]’s circuit using a 555 and a 4017B decade counter to make a display count down to 0.

The video below shows the display being put through its paces, and when the clock rate ramps up, the rhythmic pulsations of the relays driving the seven-segment flip displays is hypnotizing.

Output devices such as motors, solenoids, bulbs, buzzers, relays, LEDs, and 7-segment displays are used in many electronic circuits ... controlled by a decade counter IC for accurate counting ...