Shutter glass goes opaque when current is applied, and clear when there is none. I grabbed the following gif from Liquid Crystal Technologies.
I had the cost of 100 1″ x 3″ pieces estimated and it was in the $4,000 range. Sigh. Since this material is essentially glass, the material is fairly stiff, even in the flexible form.
You can apply an analog voltage to this, essentially being able to make this glass any color between clear and black. I would like to make a dress out of this type of material.
Just imagine a little black dress that turns transparent!