The Miami-based collector Martin Margulies has bought Ibrahim Mahama’s Non-Orientable Nkansa (2017), an installation of wooden boxes used by shoe repairmen in Ghana, priced at €375,000. On show in White Cube’s pop-up space in the Design District until 10 December, the boxes contain objects such as the original tools used to mend shoes and the slippers worn by the repairmen, as well as newer items, such as past issues of the Economist magazine. The boxes form a wall that “contains a narrative of post-independence society”, the artist told us in February, just before the work was unveiled at White Cube Bermondsey in London.