You can scale it if your printer is not big enough.

How to use the snowman maker to make a snowman in 2 minutes:
https://www.youtube.com/watch?v=LH7Uasux7gA

1.Fill the mold with snow and compress by hand
2.Scrape away excess snow with a Swiss Army Knife or straightedge
3.Place the two molds together and compress to combine the snow
4.Beat mold to loosen the snow so the mold can be removed cleanly
5.Open up the mold and drop snowman into your hand
6.Remove out any remaining snow
7.Make more and more

Enjoy and share the results on Thingiverse!

The photo was taken in Taiwan Hehuan Mountain altitude 3158m. Very beautiful. =)

Thanks Thingiverse for featuring. Some people asked me to make a snowman out of two balls instead of 3 so I made a 2 ball snowman mold. It will save material but might be weaker. Share for everyone to see!

(Thanks iamdarkyoshi translation)

This model is featured in figure 3.12 of Visualizing Mathematics with 3D Printing.

Video.
Stereographic projection is a map from the sphere to the plane: Imagine straight lines going from the north pole of the sphere down onto the plane. Each line hits the sphere in one point and the plane in one point. Stereographic projection maps that point on the sphere to the point on the plane.
If you put a light source at the north pole of this sculpture, the rays of light effectively do stereographic projection! The curves on the sphere cast shadows, mapping them to a straight line grid on the plane.
Stereographic projection is also available at Shapeways.

Update: added a version of the file with a wider base for easier printing.