I’m working on this for my entry to the latest “level-up” challenge in the tip jar section of the forums. I’ve seen joinery like this one other time online, so I thought I’d give it a try.
Basically, this is a glue-less design for a box. The long sides have a sort of “hook” sticking through the short side that is spring loaded. I have to bend down that arm to get it into the slot cut for it, then it springs back up when it gets shoved through, and it locks the sides together like that. Can be disassembled by pinching together the spring tabs again and backing them out. Bottom is simply set in a groove/slot carved into all sides, and the top slides into a similar groove into 3 sides (the fourth side is shorter, so the top can slide out over it).
I have a few adjustments to make for my final version - close up a bit of a gap on the open side of the lid, move the holes for the spring tabs just a few thousandths of an inch. Also add some nice embellishments and engraving on the sides and top, naturally. But I’m liking this. Wood is walnut for the sides, quartersawn sycamore for the top and bottom of the box. No finish applied here, since this is just a prototype I’ve been messing with, but I’ll probably coat my final box with walnut oil and be done with the finish that way.