http://users.wpi.edu/~rjduck/ece574.htm
https://www.youtube.com/watch?v=q1QwC3YlHG0
https://www.youtube.com/watch?v=PJGvZSlsLKs
https://www.youtube.com/watch?v=0age83XI8Z4
https://www.youtube.com/watch?v=IREjtgG33hQ
https://www.youtube.com/watch?v=vVYOV9MP5BA
https://canvas.uw.edu/courses/1153513
http://www.ee.ic.ac.uk/pcheung/teaching/ee2_digital/
https://ocw.mit.edu/courses/electrical-engineering-and-computer-science/6-884-complex-digital-systems-spring-2005/lecture-notes/l02_verilog.pdf