To the left is a grid showing a 10ft Sphere, with the red dot showing the origin of the sphere meeting in the corners at the grid intersection. This is the most common radius found within CTG it affects 12 Total spaces, with a maximum Width/Height of 4 spaces.

The center of the sphere is not actually the red dot but in fact the 4 squares surrounding it, meaning when a pattern describes dealing damage within the center it affects those 4 squares.