Cut the Pizza
Cut a circular pizza into 12 congruent slices, such that exactly half of them contain crust.
Remark: We say that a slice contains crust if it shares an arc with the boundary of the pizza (with non-zero measure).
SOLUTION
First, cut the pizza into 6 congruent circular triangles, and then split each of them in half, as shown on the image below.
We do not know where this puzzle originated from. If you have any information, please let us know via email.