Chapter 7 of Carpentry Fundamentals: Level One, the section on roofing, is all my geometry nightmares come to life. Rise, run, slope. Shudder, cringe, despair.

Just about the time the instructor was explaining how to use a framing square to determine the difference in length between a common rafter and the first hip or valley jack, Polly whispered to me, “I’m starting to realize builders are really smart.”

Indeed, they are really smart—in so many ways that I am not. I am smart in a crossword puzzle kind of way. Need a 7-letter-word for French architect known for a roof with two different slopes? I’m your girl. Need to calculate compound cuts to tie a hip roof into a gable?  Pass.

But I’m convinced the mental contortions of calculating cripple jack rafters and where to make the seat cut for the bird’s mouth will preserve brain plasticity and forge more new neural pathways than a thousand crossword puzzles ever will, so I’m all in.

A framing square is a thing of beauty, possibly even magic. Best I can explain, it’s an L-shaped ruler that laughs in the face of computers by synthesizing these two facts:

1. All reasonable roofing will be done with rafters 16 or 24 inches on center.

and

2. Pythagorus was a badass.

Then it tells you how long to cut rafters, based on the slope of your roof. There was a moment today when I totally grasped it. Then it was gone.

For a moment today, I thought my biggest problem was remembering which way to hold the framing square when trying to mark the cuts on the rafter. So I practiced that over and over, as if it were a dance move.

But then I realized I have a much more fundamental problem, which will prevent me from ever successfully roofing a house with my own hands:

I’m afraid of heights.