Biscuit is on the floor, stalking Preston who is sitting up on a ledge that is 20 feet off the ground (see really badly-drawn pic). Biscuit is creeping toward the wall at a rate of .5 ft/sec. How fast is the angle of observation (between Biscuit's line of sight to Preston and the floor) changing when Biscuit is 14 feet from the wall? Is the angle increasing or decreasing