The invention of 3-D printing is changing many fields, and none more so than recreational mathematics.

For the first time, mathematical artists and puzzle designers are able to create products without worrying too much about the complications of manufacture, distribution and marketing.

A centre for this activity is Shapeways, the Dutch-American company that 3-D prints on demand and provides a marketplace for individuals to sell their inventions.

If you haven't looked through the site before here are some of my favourite items, which would make geeky relatives very happy come December 25.

Craig Kaplan, a computer science professor at the University of Waterloo, Canada, is a world expert in tiling patterns…and futuristic coffee cups.

Oskar van Deventer is probably the world's most innovative puzzle designer. The 17x17x17 Rubik-style cube is just one of his many mechanical puzzles.

At the other end of the scale, this cube puzzle is 7.5mm across.

The Klein bottle is a mathematical object that has only one surface, like a 3-D Moebius strip. The Klein bottle opener is a good pun:

And if you like misanthropic dolls, you can't get more wistful than Sad Little Keanu Reeves: