I am also drawing some drills.
I drew a through-line for the whole form, then a series of ellipses with their long axes perpendicular to the through-line, then gave the ellipses some height and connected them to the next ellipse.
What really makes them look like a complex structure are just a couple of off-shoot strands on top of the basic screw form. That and making sure that the lines that don't run along the curve of the screw curve the opposite way.
The thin as shit yellow paper is where I constructed the thing before tracing it to the better paper.