| P.16 (Image to Show the Key Down) | HERE |
| P.18 (Change Once Only: boolean isDown) | HERE |
| P.20 (Play the Note) | HERE |
| P.21 (Play the Note if "g" is down) | HERE |
| P.24 (Make the Code of Key Class More Generic) | HERE |
| P.27 (Add a Key at Specified Position When the Program is Run) | HERE |
| P.30 (Update Piano() of Piano Class) | HERE |
| P.31 (Add Another Key) | HERE |
| P.33 (Add All 12 White Keys) | HERE |
| P.35 (Add All 12 White Keys) | HERE |
| P.37 (Add All 12 White Keys) | HERE |
| P.40 (How about Notes?) | HERE |
| P.43 (Can Include Black Keys - Different Key Images) | HERE |
| P.44 (Next, update Piano class as follows:) | HERE |
| P.47 (Add Methods to Control Key Up and Down) | HERE |
| P.48 (Update Piano Class) | HERE |
| P.49 (Add pressKey and playSong Method to Piano Class) | HERE |
| P.50 (Other Songs) | HERE |