Flutter is a period-2rotor component consisting of a total of six cells, with three of them being alive in each generation. Four of them can stabilize each other, as seen in phoenix 1 and other phoenix oscillators. Unlike the similar croaker, however, it can also be stabilized exclusively by stator cells, as seen in the various griddle oscillators.
It is the cheapest stabilization of the yellow cells below, which occasionally appear on the edge of an oscillator. A comparison can be seen between the flutter, which takes 3 cells, and the cheapest stable configuration, which takes 5.
