Originally Posted by Unknown Rabbit

ETA: Here, have a visual example. Given two normal animations, and one animation half the speed of the other two which switches back and forth between them, you should get a sequence like on the bottom. Of course, if the first two animations had different speeds and/or lengths, then that would make for a less regular pattern; alternatively, you might want to do something like put a trigger scenery event on the two-frame animation, to switch the level back and forth between all dancing mushrooms and all dancing flowers.