Hộp đựng Spirograph

I did not glue the knob. I just pushed it on an it holds perfectly. You can print few more boxes without lid and just stack it on.

If you have too many kids, you do not need to print all things for every single kid. You can have for example one full set of lid and box (it is more than enough for storage of four or five full sets of spirograph) and you can add one box with only big external gears. One gear for every two kids. Internal small gears can be changed between kids every time when they have ready their spiral with that one. 

So for example when you have 20 kids, you print only 4 full sets of spirograph and add 6 other big external gears. You will need only two boxes, one lid and one fidget with knob (if you want that toy there :-D ).