The Geometry of the Protractor

I noticed a clear plastic protractor resting crookedly across a sheet of graph paper on the study desk. In mathematics, clear angle measurement requires absolute precision. Placing both of my front paws against its curved outer rim, I nudged the tool forward across the grid. The smooth acrylic slid with a light rasp over the paper until its central baseline aligned perfectly with the blue pencil grid underneath. With one careful tap of my paw against the zero-degree mark, everything locked into true, orderly alignment.