Compare the material efficiency of this design versus one that uses fasteners but lays out the pattern on the plywood sheet to produce the least residual space in the "negative" cutout areas. When making donuts one can take the "holes" and make a product out of them with no additional inputs. Same for the space in between the round cookie cutter. But with round plywood pieces its destined to make a lot of waste that has no use but to burn or grind up to a sawdust and be glue pressed into a particle board (with more inputs). Not having seen the layout template, my guess is that this is substantially less efficient than it could be, all for the idealolgical goal of "no fasteners".

Fair cop, John, regarding the waste in cutting a circle shape. But in this instance, it's a red herring. Most stools are circular - less shape edges to rub human legs - so any curved top stool is subject to the same waste concern, regardless of how they're then constructed. And Chmoebel do offer a square box seat also. On their website you will see a photo of the layup for the laser cutting - looks pretty efficient. Not presented here as a perfect solution, rather to show that creative thought can be applied to furniture, instead the same old, same old.