Just a small update... each wave of an ending diagonal subdivides into a zigzag abc or wxy. Wave (2) seems to be wxy type wave. Wave (3) may also subdivide into a wxy
another hint this pattern may be an ending diagonal is wave (1) itself seems to have three sub waves (abc) which is required for an ending diagonal (each wave a zigzag or wxy)
another hint this pattern may be an ending diagonal is wave (1) itself seems to have three sub waves (abc) which is required for an ending diagonal (each wave a zigzag or wxy)