fixed typo in bounds calculation
fixed typo in bounds calculation

max630/turtleart-hacks,walterbender/turtleart,max630/turtleart-hacks,walterbender/turtleartmini,walterbender/turtleflags,walterbender/AmazonasTortuga,walterbender/turtleconfusion,walterbender/turtle3D,AlanJAS/turtleart