Inspired by: http://alt-fractals.blogspot.nl/2011/04/impossible-snowflake.html
The half version is more suitable for printing. Also, it is more hollow on the inside.
Update: made one with 1 iteration more by printing the small one 18 times and glueing them together with acetone.

I tried to print this thing without having a second thought. Forgot about the overhang which was too big. The base also has very little area to stick to the bed, so after printing 3/4 mine got loose and I had to stop it. The result is still amusing though :-)
Update: the half one prints more or less fine with small overhang problems.