Tunnels and hollow spaces provide an underlying theme for this room. The hour-long Kanalvideo (1992) was put together by the artists using footage taken by an electric probe as it travels through the Zürich sewer system. Fischli / Weiss have discussed the sense of claustrophobia induced by the probe’s strangely hypnotic journey through an intricate network of tunnels. The film reflects the artists’ fascination with the hidden and the overlooked, and echoes their identification with the rubber Sewer Workers in Room 1.

In the large sculpture Question Pot (Big) (1986), the text seems to spiral in a nervous vortex around the interior. Gazing deep into the pot can induce a metaphysical vertigo as intense as the questions themselves.

Like the Question Pot, the large grey sculptures were all hand-carved from polyurethane, a foam-like material which the artists have come to use frequently in their work. The miscellany of subjects includes a bean, the structure of the ear and a piece of tubing – all suggesting an interest in interior spaces. One of the most striking of these works is Animal, which resembles a dog or a hippo without being anything precisely. It could even be a child’s soft toy. The unknown animal is also hollow, allowing the viewer to peep through its orifices to glimpse light coming in from the other side.