The game knows 5 nodes:
0  {"kind":"question","text":"Is it a mammal?","yes":1,"no":2}
1  {"kind":"answer","text":"a dog","yes":nothing,"no":nothing}
2  {"kind":"question","text":"Does it have feathers?","yes":3,"no":4}
3  {"kind":"answer","text":"a pigeon","yes":nothing,"no":nothing}
4  {"kind":"answer","text":"a goldfish","yes":nothing,"no":nothing}
3
nothing
