Burst

A burst effect issues forth in all directions from a single corner of a square within the range of the effect, spreading in all directions to a specified radius. For instance, when you cast corrosive haze, it originates at the corner of a square within 120 feet of you and creates a 20-foot burst, meaning it extends out 20 feet in every direction from the corner of the square you chose, affecting each creature whose space (or even one square of its space) is within the burst.