Codex of math and words handshake. New Cardan Grille used to decode the words 408 Rosettes Mainframe Scan: Full 9-Medallion Inventory

In the 1400s, an overlay with holes was a real, highly advanced piece of engineering hardware called a Cardan Grille or a Volvelle Aperture Overlay. Because a scribe could not change the handwritten text once the ink was dry on the vellum, the only way to run different calculations or read separate material layers was to use a physical, moving tool placed on top of the page. Millimeter-perfect dimensions for Tool B (The Volvelle Pointer Arm) and Tool C (The Stepped Wedge) so you can get a perfect match for the holes without needing steady hands to cut them [2.5]. Daniel A Demaio Hesperia California