On: 2-D Glasses

[afhof]

Obligatory 1D Glasses: http://jpgdump.com/files/5798.png

[iwwr → afhof]

Those look like Eskimo bone glasses, made to cut down on glare from the snow.

http://upload.wikimedia.org/wikipedia/commons/c/cb/Inuit_Gog...

Note that if the slit is narrow enough, it will still focus light thought the pinhole effect (also giving you polarized light (if the material is electrically conductive)).

[shasta → afhof]

0D glasses - http://image.made-in-china.com/2f0j00ivNEORGlaqgf/Pastel-Jum...