Lectern Book

An Excel spreadsheet to calculate the size of pieces to make up a book cover that supports itself an angle on the table to be easier to read.

The original is by The Cuneo Press of New England, "Type Faces", featured in a video shared by @Lett_Arc on Twitter.

I made a few rough copies then thought about the maths a bit and came up with what I think is a good set of calculations. Please let me know if you find anything out of whack with it.