module type CCC = sig .. end
Delaunay triangulation is available for any CCC system in the sense
of Knuth's ``Axioms and Hulls''
type
val ccw : point -> point -> point -> bool
The counterclockwise relation ccw p q r states that the
circle through points (p,q,r) is traversed counterclockwise
when we encounter the points in cyclic order p,q,r,p,... *
val in_circle : point ->
point -> point -> point -> bool
The relation in_circle p q r s states that s lies
inside the circle (p,q,r) if ccw p q r is true, or outside that
circle if ccw p q r is false.