Internal structure of 10.7mm dynamic kernmantle climbing rope. This nylon rope is composed of a 40 strand "two-over-two" braided sheath and a core made from seven 3-ply yarns with a single green tracer strand running parallel to the core yarns.  Note that four of the seven core yarns are S-twist (left-handed) and three are Z-twist (right-handed).   Sample from trimmed end of a used climbing rope.
David J. Fred
CC BY-SA 3.0
<span class="int-own-work" lang="en">Own work</span>