Cool project! Here's a version with hand-made decoration by my son.

@Tengrom Thanks for sharing your make. (edited)
what size magnets should I use?
what size sliders should I use?
Great idea!
The holes for the magnets are a bit to small, so I didn‘t have to use glue. maybe I‘ll make the buttons a bit higher and print them again. Currently they are hard to swipe.

@acetous_1857987 Thanks for sharing your make. I prefer to force the magnets in place with a hammer. I will make a higher version of the buttons.
@StephaneRATELET Thanks for your make.
This is a great piece with lot of utility. Fits together well.
@TroelsR_526106 Thanks for your make.