Water trapped in a window

This was brilliant.

It's patterns made by water trapped between two sheets of glass in the windows of the fantastic stair hall of the Pinakothek Moderne in Munich.

I don't know if the water got in there through condensation or some other manner, but I'd guess that it's capillary action between two almost-touching panes, together with a variety of interesting thermal conditions, which drew the water up between the sheets of glass into these funky patterns. Anyone know any better?

At any rate, I spent almost as long enjoying these windows as I did looking at the art and building! Oh, and if you fancy a bit of a wait, it's well worth viewing these at full size...