3Doodler's 3D printing pen is fantastic concept. The pen heats and cools plastic filament like a glue gun, allowing users to literally draw in the air — as long as their structure can support its own weight. The first pen went up on Kickstarter in 2013, and three years later, creators WobbleWorks are shipping the third-generation product.

The company says the 3Doodler Create is lighter, smoother to use, and has new, simplified controls which they claim will allow new users to get "up and running in seconds." The pen is $99.99 for first-time buyers, although existing customers get 50 percent off and free shipping if they want to upgrade.

The question is, though, do you actually want a 3D printing pen? It's a good concept and is probably very fun to play with, but the pen's wobbly creations aren't exactly the sort of thing you'd put up on a mantlepiece and don't seem to have much practical use. It seems like a good tool for a school (imagine using one as a prop in a science lesson!), but you've probably got to be pretty sold on the idea to buy one yourself. We'll hopefully try the Create out later in the year.