Square and T-square

Amateurs and students most time are confined to simple forms of a drawing board with a t-square to draw horizontal lines (the board was not square enough to allow for verticals also). Angles in steps of 15 degrees require 2 squares with 90-45-45 degrees and 90-60-30 degrees.
For the desktop A2 and A3 sized drawing tablets became available with a combination of t-square and protractor. I still have an A3 sized in use.