Great, i tried to get rid of the dynamic array "possibilities" by representing it using a static array of bools. This approach made it 4 times faster :)

When i have a solid wifi connection I'm going to install dmd 2.60 to compile timon's code. In the meantime I've started beautifying the source so i can follow the logic.

I still have a few questions however:
- era claims his code takes 12 seconds on the hardest supplied puzzle yet it enters an infinite loop when the puzzle isnt solvable. Is he talking about a different puzzle?

-is it normal that const ref is slower then ref?

- in an effort of trying to make the program reuse the same memory I've moved some temporary variables outside the function but the program became slower, how can this be?

- in a few hours i'll upload my newest source. I cant find that much stupid design decisions anymore that cause slowdowns yet it keeps lagging behind by an enormous amount to timon's solver. What's that much more efficient in his solution?