ZigZag is a compositional scheme used by many famous artists such as Goya Ferdinand and Julien Dupré.  ZigZag is similar to the S curve but it has a more sharp look to it. 

Examples of ZigZag:

My attempt at ZigZag:

ZigZag by Rob Gallop:

ZigZag by billaday:

ZigZag by Jdn:

All images on this site are from zigzag.gallery.sytes.org except for my attempt at zigzag.  All images are licenced for use under Creative Commons license.  Some information from jurate.atspace.com.