On the Turning Lozange of Constant Side Whose Vertices Alternate between Two Fixed Circles of a Ring.

This note is to call attention to the paper on a theorem about zig-zags between two circles. It explains the construction of a linkage composed of four equal bars P sub 1 P sub 2 P sub 2 P sub 3 P sub 3 P sub 4 P 4 P 1 d, joined at the points P sub k, with the following property With P sub 1 and P sub 3 moving in the circular groove T, and P sub 3, P sub 4 moving in the circular groove T, it is shown that the lozange P sub 1 P sub 2 P sub 3 P sub 4 can be turned around. Keywords include Elementary geometry Linkages.