The UK artist Oliver Beer is causing a stir at the 21st Sydney Biennale (until 11 June). His films, Composition for Mouths (Songs My Mother Taught Me I/II) (2018), show couples singing through each other’s faces, so the voice comes out of the other person’s nose. “It resonates with the ongoing LGBT-rights conversation in Australia,” Beer says. “But the singers are same-sex couples for musical reasons: it requires them to sing in unison, matching the resonant frequencies of each other’s mouth cavities.” Visitors to the Art Gallery of New South Wales are rather taken with all the synchronised snogging.