> P1:=plot(x^2,x=-3.8..3.8,thickness=3):
P2:=plot( {[[-2,9],[2,9]], [[-2,4],[2,4]],[[-2,4],
[-2,9]],
[[2,4],[2,9]]},x=-3.5..3.5,thickness=3,color=blue):
P3:=plot(
{[[-3,9],[-2,9]],[[2,9],[3.5,9]],[[3,0],[3,9]],[[-3,0],
[-3,9]]},x=-3.5..3.5,thickness=1,linestyle=3,color=black):
Arr1:=labeledarrow([3.4,0],[3.4,9],
[.3,.6,.6],`a`,[0,.2],20,blue):
Arr2:=labeledarrow([3.4,9],[3.4,0],
[.3,.6,.6],` `,[0,-.2],20,blue):
txt:=
plots[textplot]([2.7,11,`y=x^2`],font=[TIMES,BOLD,18]):
plots[display]({P1,P2,P3,Arr1,Arr2,txt},xtickmarks=[],
ytickmarks=[]);

>