Glass- What Is It?

I don't want to leave you laboring under a misconception [or,at least,not this particular one].Tzvi [Helen's brother the geologist] told me that flowing window glass [mentioned in recent blog] is but another urban myth; a spot of mild research tends to support this,although there seems wide disagreement on what glass actually is,most agreeing that it is neither a liquid nor a solid.What do you think? And,since you think you're so very smart,what about foams? Liquid or solid? If the beer you are drinking has a head on it,you might like to consider this conundrum.If it doesn't,it probably isn't worth drinking anyway.