Testing out the symmetry puzzle - I did something simple. I made one end a helix and the other end a sheet. Did Ideal SS on the helix, froze it, then went to pull the sheet into position - the client crashed instantly.
Symmetry puzzles haven't been working right in quite a while.
I tried this one, and got a crash on Windows when I followed the general steps SaraL listed. Pulling on the sheet seemed to cause the crash.
I got a little further using cutpoints, but hit a crash again a few minutes later while running a recipe.
Obviously some people are either lucky or very persistent and are able to make progress despite the crashes.