UPDATE 5th May 2023:

The sketch is now on GitHub (https://github.com/funnypolynomial/FlipClock, original remains here as a zip). This includes:

• Support for Arduino Mega/Mega 2560 (in addition to Uno)
• Digit wrap is now correct - 10's of minutes going from :59 to :00 won't flash :60
• Optional blank flap in 12-hour mode. " 307" vs "0307", see ENABLE_BLANK_TENS in Config.h
• Automatic DLS adjustment is off by default, see ENABLE_AUTO_DLS in Config.h
• The LCD driver has support for variants the otherwise jumble the screen, see LCD_FIXED_ORIGIN in ILI948x.h