Run demoOrient for demo.
INCIRCLE2D(A,B,C,D) is the function for finding whether point D is
inside or outside of the circle defined by A,B,C. A,B,C,D are position
vectors [x,y]
INSPHERE(A,B,C,D,E) is the function for finding whether point D is
inside or outside of the sphere defined by A,B,C,D. A,B,C,D,E are position
vectors [x,y,z]
ORIENT2D(A,B,C) is the function for finding whether point C on the
left,right or on the line AB. A,B,C are vectors [x,y]
ORIENT3D(A,B,C,D) is the function for finding whether point D on the
bottom or the top of the plane ABC. A,B,C,D are position vectors [x,y,z]