The spacing of the hinge lines needs to be about 1/2 the thickness of the material to work, but it can be smaller. A simple three line alternating with a two line works very well. Space the line gap between the slits about four thicknesses of the wood apart.
Also the cuts need to go with the grain of wood.
Inkscape had an extension that makes them automatically. But seems broken on the most recent version of Inkscape.
But the elliptical box generator does a great job, but it too has some issues that you need to track down to use.
Here is a file to play around with. This is super flexible using Proofgrade ply. It’s got more cuts than it needs since I made it for acrylic, but it might get you started.
