Animation output was broken on some generators recently Sorry, should be fixed now! Thanks to [lara] for the report.

On the plus side, we've been improving the animation-making interface. The movie button has been made (hopefully) more prominent, and there's a clearer movie scroll bar for moving back and forth between frames. Also, you can choose between animations that are cheap-and-cheerful and fast to make, and animations that are slower to make but clearer -- just click on the movie icon, and then on either the grainy "fast" button or the crisp "slow" button. Suggestions for cleverer icons are very welcome :-).