9
x y a b c d r s t 

x b - y a;
x d - d - y c + y;
b^2 + a^2 - r^2;
c^2 - 2 c + 1 + d^2 - s^2;
a^2 - 2 a c + c^2 + b^2 - 2 b d + d^2 - t^2;;

/* Example by Morgenstern
** Found in "Experimenting the Grobner basis algorithm with the AIPI system"
**  by Carlo Traverso and Leombattista Donati.
** Proceedings of ISSAC 89.
*/
