One often gets satellite images of contrails and it’s hard to visualize what’s going on, especially with racetrack contrails drifting in the wind. So I wrote a little contrail simulator applet to demonstrate the formation of a contrail under various conditions.
I have just updated this applet to display contrail grids by default. There are just two flight paths that intersect, and the grid forms as the contrails from those two paths are blown by the wind.
The Java version seems to work better at the moment, there’s a bug with the embedded version which means you have to click slightly above things. So try this:
To get the racetrack simulator, uncheck the “intersection” checkbox in the lower left.
I’ve uploaded the full source for the Processing version here.