# Christmas and Winter Holidays

In order of appearance, here’s Vi Hart things with Christmas, snow, and winter holiday theme.

# 2011

## The Gauss Christmath Special

How many presents are there in all? Framed by the song “The Twelve Days of Christmath” (a parody of the traditional, but with math things instead of birds and stuff), this Christmath special talks about triangular numbers, ways to add stuff, and a famous story about the mathematician Gauss.

## Snow Day: You’re a Linkage

A quick comment on how snow angels can be thought of in terms of mathematics, particularly the study of linkages.

# 2012

## Snowflakes, Starflakes, and Swirlflakes

The symmetry of paper snowflakes, and how to make variations with different symmetries, including rotational symmetry.

# 2013

## Sphereflakes

Another variation on paper snowflakes, this time folding and cutting entire spheres by using deflated beach balls.

## Oh What Fun

A variation on Jingle Bells, created Christmas Morning 2013

# 2014

## Twelve

An interactive hyperbolic world aligned to a 12-tone version of the Twelve Days of Christmas, in collaboration with mathematician Henry Segerman. Originally for webVR, but it should work in your browser too: http://playing.hypernom.com/twelve

Video of the work:

You can color and assemble your own 12-days dodecahedron with this dodecahedron craft: http://playing.hypernom.com/media/12_days_of_xmas_dodec_craft.pdf

And here’s just the song, The Twelve Tones of Christmas: https://soundcloud.com/vihartvihart/the-12-tones-of-christmas

## What Child is This, 12-tone trio:

For more on 12-tone music, see Twelve Tones.

## Child

An art game made for VR, expanding “What Child is This” (as heard above) into a soundscape and gamescape. You can play it in a normal browser: https://vihart.github.io/child

Video documentation:

Background soundscape:

# 2015

## Snowplace

A VR experiment in collision design and movement design, where you leave a path through a snowy landscape as you sled around collecting presents. It was programmed live over a twitch stream.

The game no longer works quite right as it was written for an old version of webVR using the spatially-tracked Vive devkit, and relies on spatial tracking for steering your sled, but the regular browser version can still be played with, kinda: http://vihart.github.io/snowplace

Some of the livestream has been archived, particularly the programming of the sled and the tree collision: https://www.twitch.tv/videos/32189265 and https://www.twitch.tv/videos/32186529

## Ephemera

A Snow Eagle endlessly melts and reforms, to wistful snowmelty music.

# 2016

Christmas is cancelled

# 2017

## Hexaflexaflakes

Another variation on the paper snowflake, this time using hexaflexagons (see the Hexaflexagons page for more on those).