Branching column

EPSN1159, originally uploaded by efroymson.

Here you can just see a bit of the top of a branching column. I can't explain it very well, but it is related (I believe) to the reversed catenary curves I mentioned earlier. Gaudi also had an interest in laboratory testing of materials, and specified different types of stone for different places, with stronger stone where the stresses were greater.

It looks like it is just stone, but that is not true. There are iron (steel?) supports running through the columns, which are hollow.