Wait, the mouseover says:

'Grandpa, what was it like in the Before time?'

'It was hell. People went around saying glass was a slow-flowing liquid. You folks these days don't know how good you have it.'"

It just occurred to me that my museum visits as a child deceived me. That hundred year old glass didn't flow! Lies! They've found panes upside down and sideways (with respect to thickness differentials) too.