DaA> RWG, it's a lovely and informative animation! Thanks! The reason I asked about the rotation is that someone disliked it, even though I added it to remedy some unrevealing poses during pauses. Just one thing: I wish it were a bit slower, and that the words remained visible a bit longer. (I never took an Evelyn Wood course.) --Dan We can't risk small children reading them aloud and getting soap stuffed in their mouth. On 2013-10-31, at 10:57 PM, Bill Gosper wrote: http://gosper.org/pyrominia.gif . Please let me know if you strongly like or dislike the slight rotation. --rwg Here's another one, perhaps showing why Julian thinks his result is too trivial to publish: http://gosper.org/pentatrapezohedra.gif --rwg