Most Obscure Function

I was looking back at some old Visual FoxPro code from a few years ago, and came across this line:

THIS.nShipAngle = RTOD(ATN2( .nShipY-tY, tX-.nShipX )) % 360

I figure that this ATN2 is the most obscure VFP function I've found a use for. It returns the arc tangent for a coordinate location, which is probably not a requirement that comes up too often in database application development :). However, when I needed it, there it was.

For interest's sake, the context of this is a clone of the video game Asteroids that I wrote. This is part of the code that aims the player's ship at the mouse pointer.