1x instanceof f: true
2x instanceof b: true
3y instanceof f: true
4y instanceof b: true
5
6Changing prototype
7
8x instanceof f: false
9x instanceof b: false
10y instanceof f: false
11y instanceof b: false
12Bound function prototype
13
14f.hasOwnProperty('prototype'): true
15b.hasOwnProperty('prototype'): false
16