Question: Affichage d'une liste de points --- Plot a list of points

hello , i m a student and i have a little question

in fact , i wrote this program bur it doesn't work until now , i dont knew why , please if you have an idea tell it to me as soon as possible ,

thanks

> restart;
> affichage := proc (L) local i, M; M := []; for i to nops(L) do M := [op(M), convert(L(i), list)] end do; plot(M, scaling = constrained, axes = none, color = red) end proc;
print(`output redirected...`); # input placeholder
proc(L)  ...  end;
> L := [`<,>`(0, 0), `<,>`(0, 1), `<,>`(1, 1), `<,>`(1, 0)];
print(`output redirected...`); # input placeholder
[Vector[column](%id = 124763340),

  Vector[column](%id = 124763404),

  Vector[column](%id = 124763468), Vector[column](%id = 124763532)

  ]
> affichage(L);
%;
Error, (in affichage) index out of bounds