A little collection of puzzles. Some easy, some very difficult...
Nails and GlueYour goal in this puzzle is to move the pieces and/or over their respective destinations, and/or , in as few moves as possible. The buttons rotate the board to the right or to the left. After each rotation the mobile pieces fall vertically. If they fall on a nail, or in the proximity of glue , they got stuck. The button Down let the blocked mobiles fall, if possible. Sometimes you can reach a dead end: the Reset button restarts the current puzzle. Below you'll find a selection of difficult problems.
I didn't perform an exhaustive search, but while generating millions of random problems, I wrote down the most difficult I found, for each board size and number of symbols (glue, nails, etc.). Below you find a little selections of some difficult problems I found.