Last night I almost pulled an all-nighter. I was up until 5:30 am trying to figure out the solution to a puzzle in aha! Insight. The web page claims the puzzle can be solved in no fewer than 22 moves, yet aha! Insight claims it can be done in no fewer than 16 moves. I tried lots of different combinations (including a solution based on a technique described in aha! Insight that solves four knights on a 3x3 board that took 26 moves), but couldn't figure out the 16 move solution until someone posted it to rec.puzzles. As it turns out, the solutions depend upon the restrictions placed on the moves, which was something I wasn't taking into account, possibly because it was late. So now I feel better.