In the garden, at the V&A Design Festival Hub, a low pavilion is spinning itself very slowly, polymer extruding from nozzles, shading the sky one strand at a time.
We're here for the Arad expedition, rational bomb shelters and delicate architectural models, very tidy signs and sketches of important buildings. Entrance is past a vast green wall, which turns out to be full of liquid, which is full of algae.
This is a working wall, fixing energy from the sun. There's no sun in here, just the bright lights of the exhibition, but maybe that is enough.