Hypothetically, imagine a situation in which you immediately need 3D glasses, and there is no opportunity to buy them in the next few hours. The easiest way to make 3D glasses: a regular box for music discs + two alcohol-based markers (red and blue).
The front cover for the disc should be enough for one pair of glasses.
1. Take a square piece and place it for a few seconds in very hot water. This will soften the material and avoid brittleness when cutting. Then take ordinary scissors (preferably with small cutting surfaces, you can manicure) and cut out plastic in the form of two ovals connected by a jumper. To avoid burrs, sand the edges of the plastic with sandpaper.
2.Then take the red marker and evenly paint over it with the left oval of your 3D glasses, and with the blue marker the right one. To achieve uniform coloring of the plastic, you can open the marker and, having taken out the alcohol rod, squeeze it onto the surface of the plastic or evenly apply a layer with a wide painting surface 3. Wait until the surfaces dry and the alcohol dye evaporates
4. For ease of use, you can attach a handle to the design - you get a compact monocle.
These glasses, of course, will differ in the quality of it produced by the factory method, however, such homemade work will allow you to feel the 3D effect
Pictures to check your 3D glasses.