LackLock

Suppose you want to stack temporarily IKEA Lack tables.
Ok, perhaps you don't want that, fair enough.
But if you want to stack temporarily IKEA Lack tables, and if you don't want them to slide, you can use this part (printed 4 times), to lock them in place (giving the LackLock name).
It is not a strong attachment, it only prevent sliding.

This is not really an original endeavor, as you can discover if you search "Lack stacker" on this site, but I didn't really find any looking the way I wanted, so I modeled mine.

You can reuse the OpenSCAD source, and change the variables (probably ep and h, if you modify l, it will no longer be the right size for a Lack table) but there is no sanity check, so modify at your own risks.

Adding holes to the model could provide a more durable attachement, by permitting to use screws. But using another model from this site is probably a better option.