Glass is one of the remarkable materials that has fascinated us for centuries. While seemingly solid it is in reality a super-cooled liquid with viscosity so high you would have to watch for thousands of years to see it flow. Glass can let us see what is on the other side or reflect what is on this side, or blend both inside and outside into a single image. But while it lets us look through, it also forms a barrier. We cannot reach through and touch what we see.
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From @cherute
In Proof of Brain