Mascheroni construction

A Mascheroni construction is a construction done using a moveable compass alone, named after the Italian geometer Lorenzo Mascheroni (1750–1800), who, in his Geometria del compasso (1797), astonished the mathematical world by showing how every compass-and-straightedge construction can be done in this minimalist way. (Since straight lines can't be drawn with just a compass, it's assumed that two points, obtained by arc intersections, define a straight line.) It is now known that Georg Mohr (1640–1697) proved the same results earlier in his obscure Euclides danicus (1672). Mascheroni, or Mohr-Mascheroni, constructions are today primarily of interest to puzzle enthusiasts who try to improve on the older solutions by finding ones with fewer steps.