Here is a simple, yet useful circuit of an Arduino 4-digit 7-segment LED display unit. The module used here is a self-contained, compact common-cathode module containing four 7-segment LED numeric ...

What do you do with 144 7-segment displays? If you’re [Frugha] you put them all together to create an epic clock. Each display has 8 individual LEDs — 7 segments, and a decimal point.

This time [jegatheesan.soundarapandian] is making it big by building a giant 7 feet tall 7-segment display. Apparently, the plan is to build a giant clock so he started off by making the first digit.