Short and sweet:

I call that a “Snap-It”.  It’s a laser-cut design that snaps two pieces of 5 mm (1/4 inch) plywood together without screws.  I designed several cuts before I found one that snapped together without breaking and would then hold the pieces together.  The idea is to be able to build boxes and other items with no screws or glue:

Here you can just such a box.  However, I’m finding that if two tabs are too close to each other this design is still very hard to snap together without breaking something.  I also spent a bit more time with Sketchup and my laser.

The goal was to make a holder for glass IKEA candles, but after all was said and done I found that I had made a mistake somewhere along the way:  some of the pieces are slightly the wrong width and won’t fit together.  Oh well, measure twice / laser once, right?  I’ll have another go at it this week.  It’s all about getting better, so I consider it time well spent.