Helix of Tetrahedra
Tetrahedra are arranged in triples along a straight line. The edges of the tetrahedra trace three helices. The vertices of the tetrahedra lie on a cylinder, as well as on two helices, one that turns left and one that turns right.
 R. W. Gray. "Tetrahelix Data." (Aug 1, 2016) www.rwgrayprojects.com/rbfnotes/helix/helix01.html.
 G. Sadler, F. Fang, J. Kovacs, and K. Irwin, "Periodic Modification of the Boerdijk–Coxeter Helix (Tetrahelix)." arxiv.org/abs/1302.1174.
"Helix of Tetrahedra"
Wolfram Demonstrations Project
Published: August 2 2016