Reduction compass

Late 19th-century reduction compass

The reduction compass or proportional dividers is a geometry tool with asymmetric-length branches to allow performing homothetic transformations, reproducing a pattern while enlarging or reducing its size and conserving angles. It was invented by Fabrizio Mordente before 1567.[1]

  1. ^ "Reduction Compass". Epact. Museum of the History of Science, Oxford. Retrieved 10 January 2022.