Is it cheating to take a screenshot and fiddle with the pieces to see which ones match up, and plan out my moves that way? Most levels don't need it, just a few of the ones with almost-matches ;)
And having your edges be difficult to see is probably part of the game motif (you don't know how close you can let someone get before they will hurt you) I feel it detracts from the gameplay.
yracaz: have you heard of any man being killed for cheating/adultery in the real world? I haven't, however women are regularly killed because their partner or ex partner suspects them of cheating or simply because they have left him and he still considers her a belonging (yes, in the western world e.g. US, UK) and in some countries because she has been raped. I'm sorry, but the facts don't agree with your statement.
Stop spoilers. Though it would be nice if you knew what you had already combined with what so you don't end up repeating yourself while trying to find more elements.
Funny how it's only the people that don't know how to play that think this is all luck and no skill. Read some of the posts about strategies and you'll see how to maximise your wins.