I was down in Burien on a day with some stronger winds from the north.  As I looked in the direction of Mt Rainier, my attention was drawn to the east and a string of clouds that had a very repetitive pattern.  I might have expected them to be downstream of a summit, but they were not obviously connected to a high point.  They did like someone had just discovered the clone tool in Photoshop and had not yet worked out how it creates repeating elements.  It took little time before they had dissipated, and I was left wondering what the cause was.