Alnwick Garden Vortex Sculpture

A trip to Alnwick yesterday and the water sculptures are wonderful!
They move, the water pours, trickles, slides, crescendos and dims, spins and drips...
This is in an upside down hemisphere about two metres wide. There is a hole in the bottom through which the water constantly falls, spinning down the hole to create fantastic vortex patterns.
Then water pumps back (whilst still drainiing at the same time) refilling the hemisphere, spinning around the bowl mesmerising you.
When it reaches the top of the "bowl" it overflows for a while and them begins to drain again, making the vortex grow and quiver.
Hypnotic.