How do I obtain puzzle pieces?

You can win puzzle pieces in any event that grants them as a reward, such as:

• hard levels (which can be identified by the red design of the level overview window that features an image of the Clockmaker)
• the Cryptex (the final reward for unlocking the last disc)
• reward chests from the Airship Race tournament
• Jewelry Box event (the reward is given for completing a level on the first attempt in any of the three types of chests)
• in a Time Anomaly level as an extra reward (granted upon destroying a gem with the anomaly and winning the level with it on the first try)