(*Mathematica start*)
nn = 10
a = Table[1, {n, 1, nn}];
nn = Length[a];
b = Flatten[
Table[Permutations[
Table[Table[If[n >= k, a[[n - k + 1]], 0], {k, 1, nn}], {n, 0,
nn}][[i]]], {i, 1, nn + 1}], 1];
data = Flatten[
Table[x /.
N[Solve[Total[Transpose[Transpose[b]*x^(Range[nn] - 1)][[i]]] ==
0, x]], {i, 1, Length[b]}]];
p = ListPlot[{Re[#], Im[#]} & /@ data, AxesOrigin -> {0, 0},
PlotRange -> {{-2, 2}, {-2, 2}}, ImagePadding -> 40,
AspectRatio -> 1, Frame -> True,
FrameLabel -> {{Im, None}, {Re, "complex plane"}},