A cover in the shape of a reuleaux triangle still wouldn't fall into the shaft, ...

khafra on Feb 1, 2010 | parent | context | favorite | on: You don't bury survivors - transcript of an interv...

A cover in the shape of a reuleaux triangle still wouldn't fall into the shaft, but also wouldn't roll away--it would have constant width, but its center of mass would move up and down while rolling. Apparently the UK has superior civil engineers.