Wallis' Sheldonian theatre roof

thingiverse

The roof of the Sheldonian Theatre in Oxford, built from 1664 to 1669, is constructed from timber beams that are unsupported except at the walls and held together solely by gravity.\r\n\r\nJohn Wallis, the Savilian Professor of Geometry, designed the roof.\r\n\r\n"So effective was the roof that for nearly a century the University Press stored its books, and for many years it was the largest unsupported floor in existence."\r\n\r\nEach beam is a straightforward cuboid with some notches cut out of it. Instead of whittling away at balsa wood, I decided to 3D print some.\r\n\r\nTo construct the pattern, arrange the beams on top of each other, with every beam going the same way up - the notches in the middle should be on the top side.\r\n\r\nFour beams woven together will show the general principle - rest the free ends on something, and the middle will stay aloft without any support underneath it. The pattern can grow indefinitely by adding more beams.\r\n\r\nThere's some more information about the roof of the Sheldonian Theatre in this document about the Maths in the City walking tour of Oxford.