====== Video ======

  - https://www.youtube.com/watch?v=jk8e6RQGzqw&feature=share
  - https://www.youtube.com/watch?v=y21yWgMWMc8
  - https://www.youtube.com/watch?v=m2n09fTgvEk
  - https://www.youtube.com/watch?v=qjSeedeF4KQ
  - https://www.youtube.com/watch?v=QguTy8HYMOw
  - https://www.youtube.com/watch?v=S7l1z301G30
  - https://www.youtube.com/watch?v=KRG5YoQ5aLE
  - https://www.youtube.com/watch?v=jnbANCDdGlg
  - https://www.youtube.com/watch?v=Wgo-u4RJkAg
  - https://www.youtube.com/watch?v=Yo7BPFSGrdw
  - https://www.youtube.com/watch?v=ckxEZDN1iok
  - https://www.youtube.com/watch?v=L49hxOqxMvE
  - https://www.youtube.com/watch?v=CAvKQHHNmcY
  - https://www.youtube.com/watch?v=rz3_FDVt9eg  !!!  nested data -> symbolic
  - https://www.youtube.com/watch?v=K-ss_ag2k9E
  - https://www.youtube.com/watch?v=ZdPNBF6GWBw
  - https://www.youtube.com/watch?v=GyNqlOjhPCQ
  - https://www.youtube.com/watch?v=7VGPUBWGv6g
  - https://www.youtube.com/watch?v=6PVMJE3HBN0
  - https://www.youtube.com/watch?v=RbUWwuJeUC8
  - https://www.youtube.com/watch?v=I8XWImTp8VE
  - https://www.youtube.com/watch?v=dpPJ6qu6sxo
  - https://www.youtube.com/watch?v=47XU3xnN8kQ
  - https://www.youtube.com/watch?v=3putwMZpt1E
  - https://www.youtube.com/watch?v=4vuw0AsHeGw  + ostali
  - https://www.youtube.com/watch?v=RggCAXBe6BA
  - https://www.youtube.com/watch?v=jOn9DoFmJTY
  - https://www.youtube.com/watch?v=4EOG7KwFspk
  - https://www.youtube.com/watch?v=TqXD0_tGPv8
  - https://www.youtube.com/watch?v=8jvoTV54nXw
  - https://www.youtube.com/watch?v=n5NcCoa9dDU&list=PL6il2r9i3BqH9PmbOf5wA5E1wOG3FT22p
  - https://www.youtube.com/watch?v=5d5ELjrQuNM
  - https://www.youtube.com/watch?v=Gu6P43KDA2s
  - https://www.youtube.com/watch?v=hvITFzz2Xto
  - https://www.youtube.com/watch?v=guSQmfjdP_U
  - https://www.youtube.com/watch?v=S3GcQSh4l_A&t=262s
  - https://www.youtube.com/watch?v=-tkl8UYVFT4
  - https://www.youtube.com/watch?v=vOKIfrzP9Ck&list=PLDFE82708010A4615
  - https://www.youtube.com/watch?v=pzqBVzABTxA
  - https://www.youtube.com/watch?v=gXdgMnDPxuo