Vortices are patterns of rotating air left behind by wings as they generate lift. If you're interested in the physics, click here. If you're interested in pix, you're in the right place.
Below, NASA added colored smoke to the plume to measure the effect of vortices on the air behind landing aircraft. Result: Vortices are awesome.
Okay, no more text. Just a couple more pix, then a gif…
Test fly 7 Grams of Lead: Scribd has an excerpt including the first three chapters. Click here.