Math puzzles/brain teasers.?

There are puzzles that you have to draw but you can't pick up your pen and you can't go over any lines that have already been drawn. I'm wondering if these have a particular name. There is one where it is a box with two diagonals and a triangle on top (like a house). I also know of one with the box and diagonals and 4 half circles on each side. If this has a name or you know how to solve it- please let me know.