>Mate!  That's easy!  Take a glass filled to half its height with beer.
Depending on the Theory of Relativity, it's either half-full, or
half-empty!:-)))<

Or maybe the glass is too big. That's how brewers around here have masked
price increases for quite a while.

And by all means avoid pubs called Schroedinger's where they make you pay
at the bar.

M