The first room of Zineb Sedira’s exhibition Dreams Have No Titles (at the Whitechapel Gallery until 12 May) is both inviting and confusing. A dancefloor has been framed on the parquet, labelled here and there with small crosses of coloured tape – whose moves are being plotted? On the outskirts: café-style chairs and tables, almost-art-nouveau bar stools, a fringe of potted shrubs. Overhead, six mirror-balls compose a glam orrery, and project a slow-moving star chart onto the well-stocked bar beyond. There are two large radios, a wall clock stopped at a quarter to twelve, a bottle and a couple of glasses (slightly dried up) of Vin d’Algérie on the counter. Behind the bar, black-and-white photographs that might be film stills; you want to peer closer, like Jack Nicholson in The Shining. What year is it, anyway: 1924, or a century on?