Three-dimensional versions of the four card suits. Each is about 2cm tall. You'll have to paint or dye them yourself.

This is a model of Boy's Surface, a one-sided surface with no edges and no pinch points.

In the cutaway images you can see a small ball. It can roll in three directions but is trapped in the space cut out by the single-sided surface.

The ball is visible through a single cut that winds around the surface.

Note: The ball is red for clarity in the screenshots only. The entire model will be the same color when printed.

Other versions:

Without the ball: http://www.shapeways.com/model/237518/trapped_outside__track_.html

Solid, hollow inside: http://www.shapeways.com/model/233704/trapped_outside__solid_with_hole_.html

Solid: http://www.shapeways.com/model/233703/trapped_outside__solid_.html

Remember to give this model five stars if you like it!

© 2009, Matt Chisholm. All rights reserved.

The green knot revolves twice, making three full rotations along the way. It forms a rectangular cross section and a triangular hole.

The blue knot revolves three times, making two full rotations along the way. It forms a triangular cross section and a rectangular hole.

The two knots fit perfectly together, and only orbit each other by moving together.

Inspired by Oskar van Deventer's original Knotted Gear: http://www.shapeways.com/model/11915/knotted_gear.html

The first few rotations of the knots will feel a bit rough, but once you gently rotate them ten to twenty times, they smooth out. Also, the knots rotate much easier in one direction than in the other.

This is a puzzle proof of the Pythagorean theorem starting from triangles instead of squares. The puzzle is actually quite difficult.

Inspired by Magic's puzzle: http://www.shapeways.com/model/26231/pythagoras_puzzle__small_.html

This is a model of Boy's Surface, a one-sided surface with no edges and no pinch points.

This is a modified version of Trapped Outside, without the cut-away track or internal ball. This version has a tiny hole at the three-way intersection point so that Shapeways recognizes the internal space as empty and doesn't charge for it. The hole is so small it will not be printed, and the interior will be filled with support material.

Other versions:

The original design is here: http://www.shapeways.com/model/40473/trapped_outside.html

Without the ball: http://www.shapeways.com/model/237518/trapped_outside__track_.html

Solid: http://www.shapeways.com/model/233703/trapped_outside__solid_.html

Remember to give this model five stars if you like it!

© 2011, Matt Chisholm. All rights reserved.