Blind Slot Machine

Eric Fuller produced a bunch of these about 10 years ago… he’d intended to produce a slightly harder version of Stewart Coffin’s Slot Machine which ordinarily has a clear top to the box. That bit went as planned, but when it came to cutting the slot in the top of his boxes, he inadvertently cut them on the wrong side, so he ended up with a Reverse-Blind-Slot-Machine – although he settled on Blind Slot Machine in the end.

This design is a classic Coffin puzzle – it looks straight-forward: you have to put a series of polyominoes into the box through a slot in the top to make up a 3*3*3 cube inside the box. There are seven polyominoes and each of the pieces can fit through the slot(!). There are only so many ways to may up a cube from the pieces you’re given and the shape and position of the slot will dictate which pieces can go in last and in what orientation they would need to be in… which narrows things down quite a lot…

So pretty early on in the solving process you find yourself knowing exactly which assembly you’re targeting for the cube, which orientation it has to be in and which pieces are going in last – should be a doddle from there, eh?

Remember I said it was a classic Coffin puzzle?

Well, it is … which means that it’s anything but simple – even when you know EXACTLY what you’re trying to do… in fact in the beginning of the solution there is a sequence that is thoroughly mind-bending – so few combinations yet so thoroughly boggling! Several times I found myself going right back to basics, convinced I must have missed something somewhere because what I’m trying to do is quite simply impossible…

…and you’re doing everything by feel, remember? Feel and logic. Because there’s no little window to peer through and your finger is going to be jammed through that slot in the top of the box for quite a while…

Hugely satisfying solve when you finally manage to execute that tricky little bit – well worth putting all the remaining pieces in just so that you can say you have…