$ python3 design-fifteen.py
[15, 10, 3, 14, 12, 11, 9, 1, 8, 5, 0, 4, 13, 7, 6, 2]
[]
Your move? 3
making move 3
[]
==============================
Your move? 2
making move 2
[]
==============================
Your move? 99
making move 99
[]
==============================
Your move? zebra
making move zebra
[]
==============================
Your move? -1
quitting...