restart:
with(Maplets[Elements]);
with(combinat, randcomb,powerset);

#  
problem3 := proc()
local respond,   U, finished, A, answer, m, CurrentMaplet;
   respond := (m,n) -> if (m=n) then RETURN(CORRECT) else RETURN(INCORRECT) fi; 
randomize();
U:={0,1,2,3,4,5,6,7,8,9,10};
  finished := false;
  while (not finished) do
     A:= randcomb(U,2);
      answer := powerset(A);

      m := Maplet( Window( 'title'="Power Set", [[[cat("Let set A be ",convert(A,string),".")],  "What is the powerset of A?",TextField['TF1'](20)], 
        TextBox['TB1']('editable' = 'false'),
        [Button("Check", Evaluate('TB1'='respond(TF1, answer)')),
         Button("Quit", Shutdown("0")),
         Button("Another", Shutdown("1"))]
        ] ) ):

       CurrentMaplet := Maplets[Display](m);
       if (CurrentMaplet = "1") then finished := false else finished := true fi;
    end do;
end proc;

problem3();