[ An interesting CAD of R^2 to plot ]
(x,y)
2
[ (x^2 + y^2)^4 - 7 x^6 y + 35 x^4 y^3 - 21 x^2 y^5 +
  y^7 <= 0 /\ 2 y < x^2 + 1 ].
p-2d-cad -1.25 1.25 -1.25 1.25 0.005 cad2.eps
quit
