Remember these grids? Old fashioned graph paper. This one, in particular, is a bit of historical artifact, made by the drafting instrument and supplies company, Keuffel and Esser. Calculators and computers basically made the products of K & E obsolete. (Besides graph papers, K & E also made drafting tools and slide rules.) How ironic this antique should now find use as a WPC image.
Click This, TAPG! 