It sounds a lot like a View-Master. View-Master disks are about 90 mm in diameter (about 3 3/8 inch) and usually have a wide paper like sandwich with 7 PAIRS of tiny slides. The viewer looks a little like a pair of binoculars, but has frosted panels on the surface away from the user's face. A lever on the right side rotates the disk to show the next pair of slides. The point of view of each image in the pair is shifted slightly to produce a sometimes striking 3 D effect.
some stores stocked dozens of different disk sets, each set containing three disks. Many sets included photography of popular tourist attractions, historic sites and cartoons. The character cells in each pair of cartoon images were shifted more than the backgrounds to produce a layered 3D appearance. Some cartoon characters were modeled in stationary 3D models that resembled the more recent Claymation characters.
The standard viewer had to be aimed towards a light source to illuminate the frosted back panels. A deluxe viewer had a pressure bar across the top to activate a battery operated back light. For a while a variant of the disks had a phonograph like sound disk attached to the back to play back brief sound clips (required a special sound version of the viewer).
The manufacturer eventually purchased the manufacturer of a competing product that used a column of stereo images on each side of a rectangular card.
View-Master - Wikipedia, the free encyclopedia
A lot of tourist attractions sold CHEAP mini slide viewers that only had a single eyepiece for displaying flat photographs of the attraction. One variation was able to use interchangeable strips of still pictures that resembled a SHORT strip of 8 mm movie film.
Linear Mode
