It's just a virtual timer for your desktop. This is the beginning of a clock app I'm making. The other app will be an actual nixie clock, not a timer. It will also have other clocks.
If you want to mod this to exceed the limit of 59 minutes, I would love that, but I'm not sure how. It will have to draw some more tubes for that.

Anyway, here's the code for quick reading:
https://pastebin.com/BfvHmDLF
But to use it, you will need this archive containing everything:
https://drive.google.com/uc?export=down ... iq5gbsYuFG