Recursive Solutions
Summing a list of numbers
https://trinket.io/python3/3fc6942d2f
Sum the counting numbers up to 20
https://trinket.io/python/2e8cf2b456
Factorial
https://trinket.io/python3/ab3e92b2d1
Fibonacci
https://trinket.io/python3/dce6382d1f
Towers of Hanoi
https://trinket.io/python/d425c2e31e