Methods
Draws an arc originating in (x,y)
This is the standard contructor for this class and should not be used directly
Draws a circle originating in (x,y) and having the r radius
Draws a line from (x1, y1) to (x2, y2)
Plots at the given coordinates
Draws a rectangle originating in (x,y) and having the (w,h) width, respectively height