What is it?

We had a leadership offsite meeting today.
A useful day by my reckoning.

It was at the lovely Norton House Hotel which has massive grounds and a spa.
(not that we were taking in any of that; stuck in a meeting room for the majority of the day)

This structure was outside our meeting area when we went out for a spot of fresh air at lunchtime. Looks like a piece of modern art.

Well it turns out it's a chimney, letting out heat from the underground spa complex.
Nice touch form and functional.