The intermediate points can be moved sideways as well as up and down. In
this weave of a cube the points follow a sideways path like an S.
View this model with the command
poly_weave -p C1,1,1:0.02,0.08:-0.06,0.08:0.02,0.08:0.02,-0.08:0.04,-0.12:0.02,-0.08:FEV cube | off_color -f U -e F -v F | antiview -v 0.025 -e 0.025 -x f