that a sufficient length of the sliver exists on the inlet side of the piecing assembly to obtain a desired piecing operation. Then, a feeding operation of the first sliver is commenced by rotating the rollers, while a feeding operation of the second sliver from a full can by means of the feeding assembly is also commenced so that a front end of the second assembly is introduced into the inlet side of the piecing assembly so that the second sliver from the can is combined with the first sliver from the can which is nearly emptied. When the combined first and second slivers reach the drafting rollers of the piecing assembly, a draft ratio by the drafting rollers, which is a ratio of the rotational speed ofonly to Aristophanes’s comedy The Frogs, but to the ancient Ilissos river that the museum’s gardens reputedly straddle. Patterson has joyfully played on the fact that, in the 5th century BC, the area was known as Frog Island.

Migration blues … some of the 54 lambs in Africa Blessing by Aboubakar Fofana. Photograph: Stathis Mamalakis

This is the 14th Documenta. Its original mission, in a town that had felt the full force of Allied air raids, was to bring modern western art to audiences denied its pleasures by the Third Reich’s ban on works it regarded as degenerate. Such was its success that it became a five-yearly institution.

From the outset, the dual location has been controversial. No other edition has faced such expectation of failure or success. The double act