I was doing some analysis and I reached the following position WHITE TO MOVE:
You probably need to stare at this position to figure out what's going on. Currently black has a serious threat of Bd6 winning on the spot. There are a few moves that come to mind to try to defend against it. Obviously white must move his f-rook, but only one square works, can you figure it out? Don't just stop at the first move, think of critical variations, even after the correct response (or incorrect responses) white still must find some tricky moves. I'll leave this to ponder for a couple of days. Your choice between Rfb1, Rfc1, Rfd1, and Rfe1.