![Framing square.](https://myfixituplife.com/wp-content/uploads/2012/06/F__Square.jpg)
It’s counter-intuitive to think about how a square—and L-shaped piece of steel—can lay out an angled
![F__Square Framing square.](http://myfixituplife.com/wp-content/uploads/2012/06/F__Square-241x300.jpg)
![F__Square Framing square.](http://myfixituplife.com/wp-content/uploads/2012/06/F__Square-241x300.jpg)
structure like a stair carriage or rafter. This drawing from Free-Ed is a great illustration of what it is really doing: showing the carpenter what the angle is across a square in space. Up, over; rise, run.