https://www.youtube.com/watch?v=aIYwYKbBwBo
https://www.youtube.com/watch?v=KcgibHqPfVE
https://www.youtube.com/watch?v=IxSamlvP3AU
https://www.youtube.com/watch?v=MixlIbB7C5E
http://nosoftwarepatents.wikidot.com/tensors
https://www.youtube.com/watch?v=2EyMyDa0Nkk 5