This illustrates how to determine the force required to turn a connecting rod of a steam engine.
"Shear is a particular form of strain produced by causing plane layers of a material to slide parallel…
"This is bounded by four equilateral triangles and is identical with the regular tetrahedron of geometry."…
"This is bounded by twelve pentagonal faces, but these are not regular pentagons, and the angles over…
"...resembles in general appearance the regular icosahedron of geometry, but only eight f the faces…