https://www.youtube.com/watch?v=1PURNgMLOqA
https://www.youtube.com/watch?v=2GhPUAVgHZc
short circuit 1 and 2
https://www.youtube.com/watch?v=3pqz_ZCjWkc
https://youtu.be/ebILIKHi9wo?si=s3srflusrnPZYxqF
https://www.youtube.com/watch?v=KIYiGA_rIls
https://www.youtube.com/watch?v=Tm9U0Q-HuqQ
https://www.youtube.com/watch?v=FX4U6XWYvus
https://www.youtube.com/watch?v=Bwji6fxl7IU
https://www.youtube.com/watch?v=h7H73jpgX3U