From the 1950s onwards, technological advances meant that projectors became an important and helpful resource in modern teaching. One of these projectors was called an adiscopio, designed by a teacher called Luis Adiego and patented and manufactured by Enosa in the 1970s. The adiscopio is a projection system that uses slides called diakinas, which consist of a plastic frame containing four transparent squares with images on them. The device would project the four pictures onto the same projection point, enabling constant projection. Two adjacent images could be overlapped, or could fade or quickly transition into the other, giving the impression of movement.
Enosa sold sets of five or 10 diakinas on a certain topic, along with a user manual and a teacher's handbook explaining what activities they could do with this equipment.