MODULE Tile;

IMPORT Geometry, Shape, Angle;

PROC TrianglePath(a, b, c) IS 
  PS.MoveTo(a); 
  PS.LineTo(b); 
  PS.LineTo(c); 
  PS.LineTo(a) 
END;

PROC Triangle(a, b, c) IS 
  TrianglePath(a, b, c); 
  PS.SetRGB(0.2, 0.6, 0.6); 
  PS.Fill(); 
  TrianglePath(a, b, c); 
  PS.SetRGB(0, 0, 0); 
  PS.Stroke() 
END;

PRED TrapezoidHV(s, t, x, w, a, b) IS 
  (E v ~ (0.9, 0) REL (s, t) :: 
    Geometry.Colinear(s, v, t) AND 
    Angle.Right(t, v, w) AND 
    s HOR x AND 
    t VER w AND 
    (s, t) PARA (x, w) AND 
    (a, b) CONG (v, w)) 
END;

PROC Board(a, b) IS 
  Shape.Rect(a, b); 
  PS.SetRGB(0.6, 0.3, 0.3); 
  PS.Fill(); 
  Shape.Rect(a, b); 
  PS.SetRGB(0, 0, 0); 
  PS.Stroke() 
END;

PROC Test() IS 
  SAVE PS IN 
    PS.SetRGB(1, 0, 0); PS.Fill() 
  END 
END;