Archimedes's favourite insight printed in 3D

From the article Archimedes's favourite insight printed in 3D :
Archimedes's favourite insight printed in 3D, 30 January 2013 Magazine issue 2902.

ARCHIMEDES was at the cutting-edge of Ancient Greek technology but he might have increased his ability to engage with ordinary folk had he access to a 3D printer. One of the polymath's favourite proofs was showing mathematically that a sphere that fits exactly inside a cylinder fills two thirds of its volume. A representation of this was displayed on his tomb. Now, to mark the 2300th anniversary of his birth, Elizabeth Slavkovsky and Oliver Knill of Harvard University have used a 3D printer to create an object of the precise dimensions needed to demonstrate the insight visually. This article appeared in print under the headline "3D-printed proof of Archimedes"