One looks kind of like a goat sitting, licking its back.
The other one looks a lot like an angel with hands extended.
Ink blot shapes aside, they are a good visual representation of what happens behind an engine each cycle, and why augmenters work, and why they are shaped the way they are.
A little trick you can do to design a very well optimized augmenter is to fill the engine with a large charge of propane and air, and take a long exposure picture of the path the exhaust plume takes. You can see the vortex shape and path quite clearly, and its shape will literally help you define a perfect custom augmenter, no math, no generalized formulas. It will also give you a good idea of where the augmenter needs to go. Nice being able to see things that would otherwise be invisible eh?
The best way to do it is to do a number of shots, and super-impose them in a photo program, so you can average the results.
The two short fat plumes are from 8" long straight tubes, simple fireball launchers, the next from a chinese valveless.
Over fueling the duct does not really provide any more bang than the normal operational size charge, but it does fill the vorticies with burning gas for us to see.
