NeckEversion by Bernard Morin, Francois Apery, Chris Hartman, 1992
Uses jsSkel31aug17 and glsimGKF.js by David Eck.
The illiMath Collective since 1991 to 2018
(b)inoc fl(y) sha(p)e (s)kin [z]ap {f}ore {a}ft, {>,<}evert