[imtringued]

I once tried a puzzle with a significant amount of almost completely black pieces. It was faster to just brute force the pieces than to even bother looking at their shape. All you do is sort the pieces by the number of tabs/holes, look at a specific spot you want to fill and then mindlessly try every eligible piece.

[pimlottc]

This is basically my end game strategy for puzzles once all the parts with distinguishing patterns has been solved and you’re left with e.g. a bunch of blue sky pieces. It’s a bit dull, especially the sorting st the beginning, but it gets satisfyingly faster as you near the end and the number of candidates gets progressively smaller.

[shiroiushi]

It depends on the puzzle, but one problem here is when there's multiple possible pieces that fit. I have a 3000-piece puzzle where the blue sky was like this: many of the pieces were nearly identical, so there were multiple pieces that could fit together at any point. You'd only figure it a piece was in the wrong place when you couldn't fit any of the neighbors.