Parabolic Reflector — Archimedes may have used mirrors acting collectively as a parabolic reflector to burn ships attacking Syracuse.
Photo Credit: By Finnrind (original); Pbroks13 (talk) (redraw) - Image:Archimedes Heat Ray conceptual diagram.png, CC BY-SA 3.0, https://commons.wikimedia.org/w/index.php?curid=4233991