A single repetition of the wave is misleading. For N repetitions of the wave you need N + 1 buttresses not 2 N.

Also, while brick is stronger in compression a buttress increases toppling resistance in both directions so you need to consider material properties not just the geometry.

> A wavy wall with a wave amplitude of X has the same toppling resistance as a straight wall with buttresses on both sides of length x/2.

Where did you get that number from, and how does it change as you vary the distance between buttresses?