Science Art: Scheme of quadrocopter impellent (X and H configuration), by Ulrich Heither

Scientific illustration of a quadrocopter drone's propeller directions.
Scientific illustration of a quadrocopter drone's propeller directions.

This looks like a heraldic emblem to me, but it’s not. It’s also not merely an abstract diagram of circular forces, though that’s a little closer. It’s a schematic of a quadrocopter – a drone, in other words – in an X-H configuration. I think you can see the X and the H in the picture. They’re the shapes of the chassis. I can’t pretend to know about the characteristics of this setup (or direction?) compared to the +/- or X/N configurations, but the same artist has illustrated all of them, with the credit line “auf Basis der Zeichnung von Tiger66, ursprüngliche Idee von Bernd vdB,” on Wikimedia Commons.