We have a rollover this week as no-one managed to spot all five changes we made to the building below, Scharoun's Berlin Concert Hall. For the chance of winning two bottles of champagne, readers are asked to spot the deliberate alterations we've made to the building above, the Hayward Gallery on London's South Bank. Clue: there are six changes.
Post your answers, to arrive by first thing Monday morning, to Ring the Changes, 151 Rosebery Avenue, London EC1R 4GB, or fax 020 7505 6701. The first correct entry pulled out of the hat wins the bubbly.