Also possible is the case of two waves superposed in such a way that the crests of the one are at the same location as the troughs of the other, and vice versa. This is shown in the drawing on the left.

There, once again, a wave drawn in blue and one drawn in red are superposed. The result, drawn in violet, is in this case a wave with much lower crests, much less deep valleys than the partial waves. As a special case of this destructive interference, partial waves can annihilate completely.