• Start from RRURUmLUmU
• Lower 90 degrees the vertical fin into a flat shape (one goes on top of the flap tile)
• The rotated tiles both become flaps, turn 180 degrees the one that is not at a corner position
• The resulting shape is a 3x2 rectangle with a stack of three tiles in the north-east corner
• Open in 3D by hinging the two highest tiles of the stack about their east side while turning down the bottom tile of the stack (a flap) 90 degrees
• Obtain in this way the final shape