The camera lucida is a 19th century drawing aid, like a mirror on a stick, that lets you trace whatever you see. But controversial new evidence shows the Old Masters used optical aids, raising questions about the purity of art. As a provocation, artists Golan Levin and Pablo Garcia decided to make their own in the NeoLucida, a $30 device that democratizes art by letting amateurs explore the intersection of technology and art history.