- The "leader" seems to cycle from one character to the next faster than it advances from cell to cell.

- The "random" groups don't look random at all to me. More like there's a series of "standing" characters left behind by the light-green leader, and behind that there's a stream of "running" characters advancing at a different rate. We only see the running characters through gaps in the standing characters, and only in cells that the leader has already visited.