[zeiziftp] Binary input of digits

Toggle buttons which add.

0..9 = +5 +2 +1 +1

For a digital clock:
0..5 = +3 +1 +1
0..2 = +1 +1

But these still possible to get nonsensical 29:00, so
0..23 = +12 +6 +3 +1 +1

For a touchscreen.

Alternatively, grids of 24 buttons for hour, 12 (multiples of 5) for minutes and +3 +1 +1.