| x instanceof f: true | |
| x instanceof b: true | |
| y instanceof f: true | |
| y instanceof b: true | |
| Changing prototype | |
| x instanceof f: false | |
| x instanceof b: false | |
| y instanceof f: false | |
| y instanceof b: false | |
| Bound function prototype | |
| f.hasOwnProperty('prototype'): true | |
| b.hasOwnProperty('prototype'): false |