you can bend/compress wood with steam. But look at the width of that bottle neck. The others I looked at (playing cards, rubicks cube, ...) can be disassembled

you can bend/compress wood with steam. But look at the width of that bottle neck. The others I looked at (playing cards, rubicks cube, ...) can be disassembled in smaller pieces that go through. That's his technique. So how do you disassemble a plank? I think it's a hollow piece of thin plywood (1 piece, no seams) that was soaked, folded up and then filled with something (resin).