Cool and comfy seats in the Umea University MIT building! I can’t remember… what is the name for a 3-D solid that has a hole or point of convergence of the sides and faces in the centre like this? I wonder if a person’s body would fill the Centre so that the volume matches the volume of an associated solid? How much fun would it be to do my math homework in ‘chairs’ like this on a rug like this!?! :-)