What do you do with 144 7-segment displays ... saving precious RAM on the Arduino. A clock wouldn’t be any good if it wasn’t accurate. A Tiny RTC supplies battery-backed time data.

To keep accurate time, an RTC (Real-Time Clock) module is used ... ve built a digital clock made out of 144 seven-segment displays controlled by an Arduino Nano. The segments are controlled ...

[David Hopkins] built a seven segment clock ... The easy part consists of Neopixels, an Arduino Nano and a DS3231 Real Time Clock. The hard part consists of Plasticard and a polymorph diffuser.