The 3 sides where I circle in black are on the wrong side of the tpu, so nothing will stick on them. The red circle is the only side where I can stick the patch into the tube piece. That’s because I seal the piece 1L on the wrong side from the beginning (including the internal reinforcement strip). The green line means there is no TPU on either sides because I had to seal a patch on the end of the piece 1L (on the 45 degrees end) to be able to get the original shape/size. 