If you have at least two children and if they are not very young anymore, sometimes [delicious] things will disappear from the kitchen, which were actually intended for the preparation of a meal.
Of course, none of the kids admits they've eaten the sweet. It can only have been the respective sibling. And -of course- they already learned to lie ... without blushing.
Consequently, you can only lock things away if you want to ensure their later availability.
There are certainly various ready-made solutions to this problem for sale in stores .... but .... if the dad owns a 3D printer and likes to design things, then something like this may come out. ;-)
The outer design can be easily adapted to other dimensions.
OpenSCAD source is included and, if necessary, it also runs with the Customizer.
In the next few days I will add a table that will allow you to pre-determine the wheels for a given combination of numbers (the corresponding Python script is almost finished).
added a table with codes for all wheel-combinations (LibreOffice-Calc, pdf, text) ... and the Python script too. The table also shows, that you better not use these wheel-combinations (lowest-middle-top):
+ 1-X-Y or 9-X-Y and
+ 2-1-X, 2-9-X, 3-1-x, 3-9-X, 4-1-X, .... 7-9-X, 8-1-X, 8-9-X