ϕ[x_] := If[-1 ≤ x ≤ 1, 1, 0]

Table[
      Plot[1*ϕ[x + t] + 0*ϕ[x - t], {x, -10, 10}, 
        PlotRange -> {2, 0}, 
        PlotStyle -> {RGBColor[0.7, 0.5, 0], Thickness[0.02]}], {t, 0, 
        10, 0.3}]