3D printing using a 3D printing pen allows you to bring your ideas into reality right before your eyes. It is a great way to quickly prototype a design. It also allows you to 3D print free-flowing shapes that may be difficult for a 3D printer to print.
Create a little creature as a mascot design for a key chain or a pin.
Create a small box or container and suggest a use for it.
Make an item of jewellery or wearable accessory (e.g. wrist band, ring, earrings, necklace, etc)
Make a hat that you can wear.