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