I made this shelf for my nephew to display some of his figurines. I ended up cutting 30 (!) layers of 3mm plywood to get a depth of 90mm. It’s about 12” across.
I cut up the shape into pieces with two versions of cut pieces so that the cut areas would be offset by alternating the two versions during assembly. One good idea I had was to label and score every piece #1-9 or A-G to make assembly easier.
As I was gluing all the layers together, I thought there’s probably a more elegant way to make this shelf, but I will say this version is very sturdy!
I made a “tube” like that once, I played around in inkscape to come up with the most efficient way to use material to stack up layers like that with dozens of smaller segments. I made it to replace a missing part on a piece of furniture for a friend, I have no idea how may “layers” it actually took but it was about that. I used cheap leftover MDF becuase the whole thing was painted and aged anyway…