Ejemplos de realización de clase

https://www.youtube.com/watch?v=u7K72X4eo_s
http://www.youtube.com/watch?v=LZmv8B7Y1kU
https://www.youtube.com/watch?v=AjI2J2SQ528
https://www.youtube.com/watch?v=cfOa1a8hYP8
http://www.youtube.com/watch?v=oP2Pt6m3yKU
http://www.youtube.com/watch?v=IIk6ZCasKRg
https://www.youtube.com/watch?v=qS0PGJ98IwA
https://www.youtube.com/watch?v=7ePQ5VY87Sw
https://www.youtube.com/watch?v=gmrUJv8mUu4