DEFINITION MODULE XYplane;

	CONST
		draw = 1;
		erase = 0;

	VAR
		H: INTEGER;
		W: INTEGER;
		X: INTEGER;
		Y: INTEGER;

	PROCEDURE Clear;
	PROCEDURE Dot (x, y, mode: INTEGER);
	PROCEDURE IsDot (x, y: INTEGER): BOOLEAN;
	PROCEDURE Key (): CHAR;
	PROCEDURE Open;

END XYplane.
