It can shows year, month, day of month, day of week, hour, minute & second by reading real time value from DS3221. For this program, it only show hour, minute & second
Youtube link: https://www.youtube.com/watch?v=AHUJfiyRclI and https://www.youtube.com/watch?v=YRLlcTRiReo
Instructables link: https://www.instructables.com/id/8x16x8-RED-GREEN-CUBE-HANDWRITTEN-CLOCK/