Which triangles are the coldest?

This joke is a pun that combines “isosceles,” a type of triangle with at least two sides of equal length, with “ice,” referencing coldness. Isosceles triangles are a basic concept in geometry, and the term is familiar to many from math class. By replacing the beginning of “isosceles” with “ice,” the joke creates a new, fictional type of triangle that sounds like it could be colder than others due to its name. The humor arises from the playful manipulation of the word to suggest that if triangles could have temperatures, isosceles triangles would be particularly cold, hence “ice-sosceles.”