## You're reading: Posts Tagged: Christmas

### Christmas Symme-tree

Christmas wrapping paper is sold in thousands of different variations, including plain, coloured, patterned, foiled and even flock, but one thing it’ll have in common is that it will repeat whatever pattern it has, regularly across the design.

I’m interested in symmetry, and was intrigued to find a curious fact about the symmetries of such repeating patterns – their symmetries are quite limited.

### Make your own bauble with icosahedral symmetry with Shapeways

Internet 3D printing emporium Shapeways has released a nifty little tool to create your own unique Christmas bauble, which they’ll print out and send to you in time for the festive season.

It works by mapping a triangular design onto a blown-out icosahedron, and applying some “kaleidoscope effects”. As far as I can tell, that means they expand and rotate the patterns so they overlap.

There’s a selection of built-in patterns you can choose from, or you can upload your own pattern to make a really unique decoration. However, because the resulting object needs to exist in the real world, you need to take care to make sure it all comes out in one connected piece. Shapeways have written some very clear instructions about how to achieve that.

Play: Ornament Creator from Shapeways

via Vladimir Bulatov on Google+, who seems to work for Shapeways now. Exciting!

### Puzzlebomb Presents: Special 2

As part of Puzzlebomb’s commitment to bringing you all puzzles, all the time, we present a special one-off edition, consisting of festive wordplay. Enjoy! Solutions will be posted in roughly a month from now.

Puzzlebomb – Specials 2

### Fractal Christmas Trees – Your Photos

Having posted about Matt Parker’s Fractal Christmas Tree last week, we’ve had quite a few photos of completed trees sent in! Here’s a Tony Hart gallery-style roundup of them.

### Matt Parker’s Fractal Christmas Tree

Stand-up Mathematician and all-round maths lover Matt Parker has been busy again, and he’s made a set of free worksheets for teachers (and, of course, interested non-teachers) to assemble paper nets of 3D fractals, including a Menger sponge and Sierpinski tetrahedron (which I’ve just learned is also called a tetrix).

There’s also a sheet for making a delightfully festive/mathematical fractal Christmas tree, with a Menger sponge base, Sierpinski branches and a Koch Snowflake star on top. Presumably those interested can make Mandelbulb ornaments and Cantor Set tinsel to hang on it. Don’t ask me how that would work.