*/
public static Constraint[] diffn(IntVar[] X, IntVar[] Y, IntVar[] WIDTH, IntVar[] HEIGHT, boolean USE_CUMUL) {
Solver solver = X[0].getSolver();
Constraint diffNCons = new Constraint(
"DiffN",
new PropDiffN(X, Y, WIDTH, HEIGHT, false),
new PropDiffN(X, Y, WIDTH, HEIGHT, false)
);
if (USE_CUMUL) {
IntVar[] EX = new IntVar[X.length];
IntVar[] EY = new IntVar[X.length];
Task[] TX = new Task[X.length];