I've build an digital clock made out of 144 7 segment displays controlled by an arduino nano. The segments are controlled by 18 MAX7219 ic's which can control up to 64 individual leds or 8 7 segment displays. The array has 144 displays made each up of 8 individual leds so the array has an total off 1152 leds you can control.
(Note: when building this clock make sure the Tiny RTC’s headers are upside down so the battery faces downwards.)
So, I finally finished this project after starting it in June 2021, it looks beautiful, now I want to make another in a different colour. My daughter said it needs to be white haha. Next step is to add a esp8266 to it to poll an NTP, I think I will make a custom pcb to put the esp8266 on which breaks out to the same pins to plug into the existing nano port to keep it neat.