A projector with film slides and a mirror one with objects and cartoons.

　 A stand with a pyramid's eye.
　　
The world with many of built-in tops (as Descartes said) mirror-walled inside. Octagons made from the geo-form of France.
　　
　 The center, a filmslide projector. The right, an object-mirror projector.　
(平凡社　世界大百科事典　から)
　 Perhaps each picture on a checkerboard was illuminated and mirrored in order. The checkerboard was fixed on the ceiling or a lintel. It is the mirror that took a round.
　　
　　
　　
　　
Where in these gates was the mirror ? On the forehead ?　
　　
With the torch of art and learning.　　　 (大辞泉から)

　 Many of Japanese shrines are dedicated to this mirror.
　 Days of old, too, had a plaything of optical pencils.