Graphics3D[{{Line[{{-3.5, -1.5, -1.}, {-3.5, -1.5, -2.}, {-2.5, -1.5, -2.}, {-2.5, -1.5, -1.}, {-3.5, -1.5, -1.}}], Line[{{-3.5, -0.5, -1.}, {-3.5, -1.5, -1.}, {-2.5, -1.5, -1.}, {-2.5, -0.5, -1.}, {-3.5, -0.5, -1.}}], Line[{{-3.5, -0.5, -1.}, {-3.5, -0.5, -2.}, {-3.5, -1.5, -2.}, {-3.5, -1.5, -1.}, {-3.5, -0.5, -1.}}], Line[{{-3.5, -1.5, -2.}, {-3.5, -0.5, -2.}, {-2.5, -0.5, -2.}, {-2.5, -1.5, -2.}, {-3.5, -1.5, -2.}}], Line[{{-2.5, -1.5, -1.}, {-2.5, -1.5, -2.}, {-2.5, -0.5, -2.}, {-2.5, -0.5, -1.}, {-2.5, -1.5, -1.}}], Line[{{-2.5, -0.5, -1.}, {-2.5, -0.5, -2.}, {-3.5, -0.5, -2.}, {-3.5, -0.5, -1.}, {-2.5, -0.5, -1.}}]}, Thickness[0.02], Line[{{-3.5, -1.5, -2.}, {-3.5, -0.5, -2.}, {-2.5, -0.5, -2.}, {-2.5, -1.5, -2.}, {-2.5, -1.5, -1.}, {-2.5, -0.5, -1.}, {-3.5, -0.5, -1.}, {-3.5, -1.5, -1.}, {-3.5, -1.5, -2.}}]}, {Boxed -> False}]