diff --git a/lib/matplotex.ex b/lib/matplotex.ex
index 3720f77..0f7c402 100644
--- a/lib/matplotex.ex
+++ b/lib/matplotex.ex
@@ -213,10 +213,6 @@ defmodule Matplotex do
     bar(pos, values, width, [])
   end
 
-  def bar(pos, values, width, opts) do
-    BarChart.create(%Figure{axes: %BarChart{}}, {pos, values, width}, opts)
-  end
-
   @doc """
   Adds an additional dataset to a bar plot in the given `%Figure{}`.
 
@@ -251,6 +247,13 @@ defmodule Matplotex do
   |> M.bar(0, values2, width, label: "Dataset2", color: "#D3D3D3")
   |> M.bar(width, values2, width, label: "Dataset3", color: "green")
   """
+
+  def bar(%Figure{} = figure, values, width, opts), do: bar(figure, width, values, width, opts)
+
+  def bar(pos, values, width, opts) do
+    BarChart.create(%Figure{axes: %BarChart{}}, {pos, values, width}, opts)
+  end
+
   def bar(%Figure{} = figure, pos, values, width, opts) do
     figure
     |> show_legend()
@@ -752,6 +755,10 @@ defmodule Matplotex do
     Figure.show_legend(figure)
   end
 
+  def hide_legend(figure) do
+    Figure.hide_legend(figure)
+  end
+
   def set_options(figure, opts) do
     PlotOptions.set_options_in_figure(figure, opts)
   end
diff --git a/lib/matplotex/colorscheme/blender.ex b/lib/matplotex/colorscheme/blender.ex
index 460d32f..9cc549b 100644
--- a/lib/matplotex/colorscheme/blender.ex
+++ b/lib/matplotex/colorscheme/blender.ex
@@ -1,19 +1,17 @@
 defmodule Matplotex.Colorscheme.Blender do
-@moduledoc false
-alias Matplotex.Colorscheme.Rgb
+  @moduledoc false
+  alias Matplotex.Colorscheme.Rgb
 
   @rgb_fields [:red, :green, :blue, :alpha]
 
   @type color :: %Rgb{
-    red: :float,
-    green: :float,
-    blue: :float,
-    alpha: :float
-  }
-
+          red: :float,
+          green: :float,
+          blue: :float,
+          alpha: :float
+        }
 
   def mix(color1, color2, weight \\ 0.5) do
-
     p = weight
     w = p * 2 - 1
     a = color1.alpha - color2.alpha
@@ -30,10 +28,10 @@ alias Matplotex.Colorscheme.Rgb
     alpha = get_alpha(color1) * p + get_alpha(color2) * (1 - p)
     rgb(r, g, b, alpha)
   end
+
   defdelegate rgb(red, green, blue), to: Rgb
   defdelegate rgb(red, green, blue, alpha), to: Rgb
 
-
   @doc """
     Gets the `:red` property of the color.
   """
@@ -87,6 +85,4 @@ alias Matplotex.Colorscheme.Rgb
   end
 
   defp cast_color_by_attribute(color, attribute) when attribute in @rgb_fields, do: color
-
-
 end
diff --git a/lib/matplotex/colorscheme/colormap.ex b/lib/matplotex/colorscheme/colormap.ex
index 1a8baee..90f52c2 100644
--- a/lib/matplotex/colorscheme/colormap.ex
+++ b/lib/matplotex/colorscheme/colormap.ex
@@ -1,20 +1,21 @@
 defmodule Matplotex.Colorscheme.Colormap do
-@moduledoc false
+  @moduledoc false
   defstruct [:color, :offset, opacity: 1]
+
   def viridis do
-    ["#fde725","#21918c","#3b528b","#440154"]
+    ["#fde725", "#21918c", "#3b528b", "#440154"]
   end
 
   def plasma do
-    ["#F7E425","#ED6925", "#9C179E", "#0C0786" ]
+    ["#F7E425", "#ED6925", "#9C179E", "#0C0786"]
   end
 
   def inferno do
-    ["#FCFFA4","#F56C3E","#B12A90","#000004"]
+    ["#FCFFA4", "#F56C3E", "#B12A90", "#000004"]
   end
 
   def magma do
-    ["#FCFDBF","#FB8861", "#B73779", "#000004"]
+    ["#FCFDBF", "#FB8861", "#B73779", "#000004"]
   end
 
   def fetch_cmap(cmap) when is_binary(cmap), do: cmap |> String.to_atom() |> fetch_cmap()
@@ -22,8 +23,10 @@ defmodule Matplotex.Colorscheme.Colormap do
   def fetch_cmap(cmap) do
     apply(__MODULE__, cmap, []) |> make_colormap()
   end
+
   def make_colormap(colors) do
     size = length(colors)
+
     colors
     |> Enum.with_index()
     |> Enum.map(&colormap(&1, size))
@@ -35,6 +38,4 @@ defmodule Matplotex.Colorscheme.Colormap do
     offset = idx / size * 100
     %__MODULE__{color: color, offset: offset}
   end
-
-
 end
diff --git a/lib/matplotex/colorscheme/garner.ex b/lib/matplotex/colorscheme/garner.ex
index d3e279a..fa3e08b 100644
--- a/lib/matplotex/colorscheme/garner.ex
+++ b/lib/matplotex/colorscheme/garner.ex
@@ -1,13 +1,14 @@
 defmodule Matplotex.Colorscheme.Garner do
-@moduledoc false
-alias Matplotex.Colorscheme.Rgb
-alias Matplotex.Colorscheme.Blender
-alias Matplotex.InputError
+  @moduledoc false
+  alias Matplotex.Colorscheme.Rgb
+  alias Matplotex.Colorscheme.Blender
+  alias Matplotex.InputError
 
-  defstruct [:range, :color_cue,  :cmap, :preceeding, :minor, :major, :final]
+  defstruct [:range, :color_cue, :cmap, :preceeding, :minor, :major, :final]
 
   def garn_color({min, max} = range, point, cmap) when max != min do
     cue = (point - min) / (max - min)
+
     cmap
     |> make_from_cmap()
     |> put_range(range, cue)
@@ -16,8 +17,8 @@ alias Matplotex.InputError
 
   defp make_from_cmap(cmap) do
     cmap
-    |>to_rgb()
-    |>place_edges()
+    |> to_rgb()
+    |> place_edges()
   end
 
   defp put_range(%__MODULE__{} = garner, range, cue) do
@@ -28,22 +29,29 @@ alias Matplotex.InputError
     Enum.map(color_map, &Rgb.from_cmap!(&1))
   end
 
-  defp place_edges([preceeding, minor, major,final]) do
-    %__MODULE__{preceeding: preceeding.color, minor: minor.color, major: major.color, final: final.color}
+  defp place_edges([preceeding, minor, major, final]) do
+    %__MODULE__{
+      preceeding: preceeding.color,
+      minor: minor.color,
+      major: major.color,
+      final: final.color
+    }
   end
+
   defp place_edges(_) do
     raise InputError, message: "Invalid colormap"
   end
 
-  defp point_color(%__MODULE__{color_cue: cue, preceeding: preceeding, minor: minor}) when cue < minor do
-   minor|> Blender.mix(preceeding, cue)|> Rgb.to_string()
+  defp point_color(%__MODULE__{color_cue: cue, preceeding: preceeding, minor: minor})
+       when cue < minor do
+    minor |> Blender.mix(preceeding, cue) |> Rgb.to_string()
   end
 
   defp point_color(%__MODULE__{color_cue: cue, minor: minor, major: major}) when cue < major do
-   major|> Blender.mix(minor, cue)|> Rgb.to_string()
+    major |> Blender.mix(minor, cue) |> Rgb.to_string()
   end
 
   defp point_color(%__MODULE__{color_cue: cue, major: major, final: final}) when cue >= major do
-    final|> Blender.mix(major)|> Rgb.to_string()
+    final |> Blender.mix(major) |> Rgb.to_string()
   end
- end
+end
diff --git a/lib/matplotex/colorscheme/rgb.ex b/lib/matplotex/colorscheme/rgb.ex
index 590c960..3c350ce 100644
--- a/lib/matplotex/colorscheme/rgb.ex
+++ b/lib/matplotex/colorscheme/rgb.ex
@@ -1,18 +1,25 @@
 defmodule Matplotex.Colorscheme.Rgb do
   @moduledoc false
-alias Matplotex.Colorscheme.Colormap
+  alias Matplotex.Colorscheme.Colormap
+
   defstruct [
-    red: 0.0, # 0-255
-    green: 0.0, # 0-255
-    blue: 0.0, # 0-255
-    alpha: 1.0  # 0-1
+    # 0-255
+    red: 0.0,
+    # 0-255
+    green: 0.0,
+    # 0-255
+    blue: 0.0,
+    # 0-1
+    alpha: 1.0
   ]
 
-  def rgb(red, green, blue, alpha\\1.0)
-  def rgb({red, :percent}, {green, :percent}, {blue, :percent}, alpha)  do
+  def rgb(red, green, blue, alpha \\ 1.0)
+
+  def rgb({red, :percent}, {green, :percent}, {blue, :percent}, alpha) do
     rgb(red * 255, green * 255, blue * 255, alpha)
   end
-  def rgb(red, green, blue, alpha)  do
+
+  def rgb(red, green, blue, alpha) do
     %__MODULE__{
       red: cast(red, :red),
       green: cast(green, :green),
@@ -21,65 +28,64 @@ alias Matplotex.Colorscheme.Colormap
     }
   end
 
-  def to_string(struct, type\\nil)
+  def to_string(struct, type \\ nil)
+
+  def to_string(struct, nil) do
+    type =
+      case struct.alpha do
+        1.0 -> :hex
+        _ -> :rgba
+      end
 
-  def to_string(struct, :nil) do
-    type = case struct.alpha do
-      1.0 -> :hex
-      _ -> :rgba
-    end
     to_string(struct, type)
   end
 
   def to_string(%__MODULE__{red: r, green: g, blue: b, alpha: alpha}, :rgba) do
     "rgba(#{round(r)}, #{round(g)}, #{round(b)}, #{alpha})"
   end
+
   def to_string(%__MODULE__{red: r, green: g, blue: b, alpha: 1.0}, :hex) do
     "#" <> to_hex(r) <> to_hex(g) <> to_hex(b)
   end
 
   def cast(value, field) when field in [:red, :green, :blue] do
-    value/1
+    (value / 1)
     |> min(255.0)
     |> max(0.0)
   end
+
   def cast(value, :alpha) do
-    value/1
+    (value / 1)
     |> min(1.0)
     |> max(0.0)
   end
 
-  defp to_hex(value) when is_float(value), do:
-    to_hex(round(value))
-  defp to_hex(value) when value < 16, do:
-    "0" <> Integer.to_string(value, 16)
-  defp to_hex(value) when is_integer(value), do:
-    Integer.to_string(value, 16)
-
-    def from_hex!(input) do
-      {:ok, color} = from_hex(input)
-      color
-    end
+  defp to_hex(value) when is_float(value), do: to_hex(round(value))
+  defp to_hex(value) when value < 16, do: "0" <> Integer.to_string(value, 16)
+  defp to_hex(value) when is_integer(value), do: Integer.to_string(value, 16)
 
-    def from_cmap!(%Colormap{color: color} = cmap) do
-     %Colormap{cmap | color: from_hex!(color) }
-    end
+  def from_hex!(input) do
+    {:ok, color} = from_hex(input)
+    color
+  end
 
-    def from_hex("#" <> <<r :: binary-size(2), g :: binary-size(2), b :: binary-size(2)>>) do
-      {:ok, rgb(parse_hex(r), parse_hex(g), parse_hex(b))}
-    end
-    def from_hex("#" <> <<r :: binary-size(1), g :: binary-size(1), b :: binary-size(1)>>) do
-      {:ok, rgb(parse_hex(r <> r), parse_hex(g <> g), parse_hex(b <> b))}
-    end
+  def from_cmap!(%Colormap{color: color} = cmap) do
+    %Colormap{cmap | color: from_hex!(color)}
+  end
 
-    defp parse_hex(s), do: String.to_integer(s, 16)
+  def from_hex("#" <> <<r::binary-size(2), g::binary-size(2), b::binary-size(2)>>) do
+    {:ok, rgb(parse_hex(r), parse_hex(g), parse_hex(b))}
+  end
 
+  def from_hex("#" <> <<r::binary-size(1), g::binary-size(1), b::binary-size(1)>>) do
+    {:ok, rgb(parse_hex(r <> r), parse_hex(g <> g), parse_hex(b <> b))}
+  end
 
+  defp parse_hex(s), do: String.to_integer(s, 16)
 end
 
-
 defimpl String.Chars, for: CssColors.RGB do
-def to_string(struct) do
- Matplotex.Colorscheme.Rgb.to_string(struct)
-end
+  def to_string(struct) do
+    Matplotex.Colorscheme.Rgb.to_string(struct)
+  end
 end
diff --git a/lib/matplotex/element.ex b/lib/matplotex/element.ex
index 2a80b6d..20e7c8d 100644
--- a/lib/matplotex/element.ex
+++ b/lib/matplotex/element.ex
@@ -17,7 +17,7 @@ defmodule Matplotex.Element do
 
       defimpl String.Chars, for: __MODULE__ do
         def to_string(%module{} = element) do
-        module.assemble(element)
+          module.assemble(element)
         end
       end
     end
diff --git a/lib/matplotex/element/cmap.ex b/lib/matplotex/element/cmap.ex
index 0494e1a..ac71971 100644
--- a/lib/matplotex/element/cmap.ex
+++ b/lib/matplotex/element/cmap.ex
@@ -1,5 +1,5 @@
 defmodule Matplotex.Element.Cmap do
-@moduledoc false
+  @moduledoc false
   alias Matplotex.Element.Rect
   alias Matplotex.Element
   use Element
diff --git a/lib/matplotex/figure.ex b/lib/matplotex/figure.ex
index 6ac9857..bdaa0c5 100644
--- a/lib/matplotex/figure.ex
+++ b/lib/matplotex/figure.ex
@@ -63,6 +63,9 @@ defmodule Matplotex.Figure do
   def show_legend(%__MODULE__{axes: %module{} = axes} = figure),
     do: %{figure | axes: module.show_legend(axes)}
 
+  def hide_legend(%__MODULE__{axes: %module{} = axes} = figure),
+    do: %{figure | axes: module.hide_legend(axes)}
+
   def set_figure_size(%__MODULE__{margin: margin, axes: axes} = figure, {fwidth, fheight} = fsize) do
     frame_size = {fwidth - fwidth * 2 * margin, fheight - fheight * 2 * margin}
 
diff --git a/lib/matplotex/figure/areal.ex b/lib/matplotex/figure/areal.ex
index 416c9d1..9c23061 100644
--- a/lib/matplotex/figure/areal.ex
+++ b/lib/matplotex/figure/areal.ex
@@ -58,7 +58,6 @@ defmodule Matplotex.Figure.Areal do
       end
 
       def add_title(axes, title, opts) when is_binary(title) do
-        # title = Text.create_text(title, opts)
         %{axes | title: title, show_title: true}
       end
 
@@ -171,6 +170,20 @@ defmodule Matplotex.Figure.Areal do
         end
       end
 
+      # For stacked bar chart the flattening supposed to be the sumation of yaxis data
+      def flatten_for_data(datasets, nil), do: flatten_for_data(datasets)
+
+      def flatten_for_data([%{x: x, y: y} | _datasets], bottom) do
+        y =
+          bottom
+          |> Kernel.++([y])
+          |> Nx.tensor(names: [:x, :y])
+          |> Nx.sum(axes: [:x])
+          |> Nx.to_list()
+
+        {x, y}
+      end
+
       def flatten_for_data(datasets) do
         datasets
         |> Enum.map(fn %{x: x, y: y} -> {x, y} end)
@@ -206,6 +219,10 @@ defmodule Matplotex.Figure.Areal do
         %__MODULE__{axes | show_legend: true}
       end
 
+      def hide_legend(%__MODULE__{} = axes) do
+        %__MODULE__{axes | show_legend: false}
+      end
+
       def set_frame_size(%__MODULE__{} = axes, frame_size) do
         %__MODULE__{axes | size: frame_size}
       end
@@ -382,6 +399,27 @@ defmodule Matplotex.Figure.Areal do
     Algebra.transform_given_point(x, y, sx, sy, tx, ty)
   end
 
+  def do_transform(
+        %Dataset{x: x, y: y, bottom: bottom} = dataset,
+        xlim,
+        ylim,
+        width,
+        height,
+        transition
+      )
+      when is_list(bottom) do
+    y = [y | bottom] |> Nx.tensor() |> Nx.transpose() |> Nx.to_list()
+
+    transformed =
+      x
+      |> Enum.zip(y)
+      |> Enum.map(fn {x, y} ->
+        transform_with_bottom(x, y, xlim, ylim, width, height, transition)
+      end)
+
+    %Dataset{dataset | transformed: transformed}
+  end
+
   def do_transform(%Dataset{x: x, y: y} = dataset, xlim, ylim, width, height, transition) do
     transformed =
       x
@@ -394,4 +432,19 @@ defmodule Matplotex.Figure.Areal do
 
     %Dataset{dataset | transformed: transformed}
   end
+
+  defp transform_with_bottom(x, y, xlim, ylim, width, height, transition) when is_list(y) do
+    y_top = Enum.sum(y)
+    y_bottom = y |> tl() |> Enum.sum()
+
+    transformed =
+      transformation(x, y_top, xlim, ylim, width, height, transition)
+      |> Algebra.flip_y_coordinate()
+
+    {_, transformed_y_bottom} =
+      transformation(x, y_bottom, xlim, ylim, width, height, transition)
+      |> Algebra.flip_y_coordinate()
+
+    {transformed, transformed_y_bottom}
+  end
 end
diff --git a/lib/matplotex/figure/areal/bar_chart.ex b/lib/matplotex/figure/areal/bar_chart.ex
index d87734e..16ae106 100644
--- a/lib/matplotex/figure/areal/bar_chart.ex
+++ b/lib/matplotex/figure/areal/bar_chart.ex
@@ -36,7 +36,8 @@ defmodule Matplotex.Figure.Areal.BarChart do
     x = hypox(values)
     dataset = Dataset.cast(%Dataset{x: x, y: values, pos: pos, width: width}, opts)
     datasets = data ++ [dataset]
-    xydata = flatten_for_data(datasets)
+    bottom = Keyword.get(opts, :bottom)
+    xydata = datasets |> Enum.reverse() |> flatten_for_data(bottom)
 
     %Figure{
       figure
@@ -126,6 +127,41 @@ defmodule Matplotex.Figure.Areal.BarChart do
     end
   end
 
+  def capture(
+        [{{x, y}, bottom} | to_capture],
+        captured,
+        %Dataset{
+          color: color,
+          width: width,
+          pos: pos_factor,
+          edge_color: edge_color,
+          alpha: alpha,
+          line_width: line_width
+        } = dataset,
+        bly
+      ) do
+    capture(
+      to_capture,
+      captured ++
+        [
+          %Rect{
+            type: "figure.bar",
+            x: bar_position(x, pos_factor),
+            y: y,
+            width: width,
+            height: bottom - y,
+            color: color,
+            stroke: edge_color || color,
+            fill_opacity: alpha,
+            stroke_opacity: alpha,
+            stroke_width: line_width
+          }
+        ],
+      dataset,
+      bly
+    )
+  end
+
   def capture(
         [{x, y} | to_capture],
         captured,
@@ -172,8 +208,6 @@ defmodule Matplotex.Figure.Areal.BarChart do
     x + pos_factor
   end
 
-
-
   defp list_of_ticks(data, step) do
     1..length(data)
     |> Enum.into([], fn d ->
diff --git a/lib/matplotex/figure/areal/plot_options.ex b/lib/matplotex/figure/areal/plot_options.ex
index 1ff8001..e119752 100644
--- a/lib/matplotex/figure/areal/plot_options.ex
+++ b/lib/matplotex/figure/areal/plot_options.ex
@@ -21,6 +21,7 @@ defmodule Matplotex.Figure.Areal.PlotOptions do
   @spec set_options_in_figure(Figure.t(), keyword()) :: Figure.t()
   def set_options_in_figure(%Figure{} = figure, opts) do
     opts = sanitize(opts)
+
     figure
     |> cast_figure(opts)
     |> cast_axes(opts)
@@ -32,14 +33,19 @@ defmodule Matplotex.Figure.Areal.PlotOptions do
   end
 
   defp cast_axes(%Figure{axes: axes} = figure, opts) do
-
     opts = Keyword.delete(opts, :label)
     cmap = Keyword.get(opts, :cmap)
     colors = Keyword.get(opts, :colors)
+    bottom = Keyword.get(opts, :bottom)
 
     %Figure{
       figure
-      | axes: axes |> struct(opts) |> cast_two_d_structs(opts)|> update_cmap(cmap, colors)
+      | axes:
+          axes
+          |> struct(opts)
+          |> cast_two_d_structs(opts)
+          |> update_cmap(cmap, colors)
+          |> update_type(bottom)
     }
   end
 
@@ -62,14 +68,19 @@ defmodule Matplotex.Figure.Areal.PlotOptions do
   defp sanitize(opts) do
     Keyword.drop(opts, @immutable_keys)
   end
-  defp update_cmap(axes, nil, colors) when is_list(colors) do
 
+  defp update_cmap(axes, nil, colors) when is_list(colors) do
     %{axes | cmap: Colormap.fetch_cmap(@default_cmap)}
   end
 
   defp update_cmap(axes, cmap, colors) when is_list(colors) do
-   %{axes | cmap: Colormap.fetch_cmap(cmap)}
+    %{axes | cmap: Colormap.fetch_cmap(cmap)}
   end
 
-  defp update_cmap(figure, _, _), do: figure
+  defp update_cmap(axes, _, _), do: axes
+  defp update_type(axes, nil), do: axes
+
+  defp update_type(axes, bottom) when is_list(bottom) do
+    %{axes | type: "stacked"}
+  end
 end
diff --git a/lib/matplotex/figure/areal/step.ex b/lib/matplotex/figure/areal/step.ex
index 11889db..11568fb 100644
--- a/lib/matplotex/figure/areal/step.ex
+++ b/lib/matplotex/figure/areal/step.ex
@@ -1,5 +1,5 @@
 defmodule Matplotex.Figure.Areal.Step do
-@moduledoc false
+  @moduledoc false
   alias Matplotex.Figure.Areal.LinePlot
   alias Matplotex.Figure
   alias Matplotex.InputError
diff --git a/lib/matplotex/figure/cast.ex b/lib/matplotex/figure/cast.ex
index a9c94c2..801eadd 100644
--- a/lib/matplotex/figure/cast.ex
+++ b/lib/matplotex/figure/cast.ex
@@ -550,8 +550,11 @@ defmodule Matplotex.Figure.Cast do
               |> Algebra.flip_y_coordinate()
               |> Algebra.transform_given_point({0, height_region_content})
 
-            {x2_cmap_tick, _} = tick_x2 = Algebra.transform_given_point(tick_coords, {tick_line_length, 0})
+            {x2_cmap_tick, _} =
+              tick_x2 = Algebra.transform_given_point(tick_coords, {tick_line_length, 0})
+
             {tick_label_x, _} = Algebra.transform_given_point(tick_x2, {tick_line_length, 0})
+
             tick_label =
               Label.cast_label(
                 %Label{type: "tick.cmap", x: tick_label_x, y: y_cord_tick, text: tick},
@@ -583,7 +586,8 @@ defmodule Matplotex.Figure.Cast do
               width: cmap_width,
               height: height_region_content
             }
-          }|>Cmap.color_gradient()
+          }
+          |> Cmap.color_gradient()
         ] ++ ticks
       end)
       |> List.flatten()
@@ -593,7 +597,6 @@ defmodule Matplotex.Figure.Cast do
 
   def cast_legends(figure), do: figure
 
-
   defp calculate_center(%Region{x: x, y: y, width: width}, :x) do
     {calculate_distance({x, y}, {x + width, y}) / 2 + x, y}
   end
diff --git a/lib/matplotex/figure/dataset.ex b/lib/matplotex/figure/dataset.ex
index ca84be5..ae23b1e 100644
--- a/lib/matplotex/figure/dataset.ex
+++ b/lib/matplotex/figure/dataset.ex
@@ -24,7 +24,8 @@ defmodule Matplotex.Figure.Dataset do
     marker: @default_marker,
     linestyle: @default_linestyle,
     marker_size: @default_marker_size,
-    line_width: @line_width
+    line_width: @line_width,
+    bottom: nil
   ]
 
   def cast(dataset, values) do
diff --git a/lib/matplotex/figure/sketch.ex b/lib/matplotex/figure/sketch.ex
index 5b4a1e0..dcd7338 100644
--- a/lib/matplotex/figure/sketch.ex
+++ b/lib/matplotex/figure/sketch.ex
@@ -19,8 +19,6 @@ defmodule Matplotex.Figure.Sketch do
     end}"
   end
 
-
-
   defp wrap_with_tag(svg, width, height) do
     ~s(<svg width="#{width}"
       height="#{height}"
diff --git a/test/matplotex/colorscheme/garner_test.exs b/test/matplotex/colorscheme/garner_test.exs
index 73f7d67..ce2395e 100644
--- a/test/matplotex/colorscheme/garner_test.exs
+++ b/test/matplotex/colorscheme/garner_test.exs
@@ -5,13 +5,13 @@ defmodule Matplotex.Colorscheme.GarnerTest do
 
   describe "garn_color/3" do
     test "garn the color for specific point in the number" do
-      colorset = [3,4,5,6,6,4,9]
+      colorset = [3, 4, 5, 6, 6, 4, 9]
       viridis = Colormap.fetch_cmap(:viridis)
       color = Garner.garn_color(Enum.min_max(colorset), Enum.min(colorset), viridis)
       assert is_color(color)
     end
   end
 
-  defp is_color("#" <> <<_r :: binary-size(2), _g :: binary-size(2), _b :: binary-size(2)>>), do: true
+  defp is_color("#" <> <<_r::binary-size(2), _g::binary-size(2), _b::binary-size(2)>>), do: true
   defp is_color(_), do: false
 end
diff --git a/test/matplotex/figure/areal/bar_chart_test.exs b/test/matplotex/figure/areal/bar_chart_test.exs
index df39618..8afd591 100644
--- a/test/matplotex/figure/areal/bar_chart_test.exs
+++ b/test/matplotex/figure/areal/bar_chart_test.exs
@@ -15,8 +15,30 @@ defmodule Matplotex.Figure.Areal.BarChartTest do
       assert %Figure{axes: %{element: elements}} =
                BarChart.materialized_by_region(figure) |> BarChart.materialize()
 
-      assert assert Enum.filter(elements, fn x -> x.type == "figure.bar" end) |> length() ==
-                      length(y)
+      assert Enum.filter(elements, fn x -> x.type == "figure.bar" end) |> length() ==
+               length(y)
     end
+
+    test "bottom variable in opts makes stacked bar chart and it will stack the bars" do
+      values1 = [2, 4, 3, 2]
+      values2 = [1, 2, 1, 4]
+      values3 = [3, 1, 2, 1]
+      width = 0.3
+
+      bar =
+        Matplotex.bar(values1, width)
+        |> Matplotex.bar(values2, width, bottom: [values1])
+        |> Matplotex.bar(values3, width, bottom: [values2, values1])
+
+      expected_elements_count = (values1 ++ values2 ++ values3) |> length()
+      assert %Figure{axes: %{element: elements}} = Figure.materialize(bar)
+      bar_elements = Enum.filter(elements, fn x -> x.type == "figure.bar" end)
+      assert bar_elements |> length() == expected_elements_count
+      assert Enum.all?(bar_elements, fn rect -> assert_valid_coords(rect) end)
+    end
+  end
+
+  defp assert_valid_coords(rect) do
+    rect.x > 0 and rect.y > 0 and rect.width > 0 and rect.height > 0
   end
 end
diff --git a/test/matplotex/figure/areal/plot_options_test.exs b/test/matplotex/figure/areal/plot_options_test.exs
index 807dc15..4595875 100644
--- a/test/matplotex/figure/areal/plot_options_test.exs
+++ b/test/matplotex/figure/areal/plot_options_test.exs
@@ -28,12 +28,15 @@ defmodule Matplotex.Figure.Areal.PlotOptionsTest do
       refute figure.axes.element == nil
       refute figure.axes == nil
     end
+
     test "updates cmap as a list by its name" do
-    assert %Figure{axes: %{cmap: cmap}} =   [1, 2, 3, 4, 5, 6]
-      |> Matplotex.plot([1, 2, 3, 4, 5],
-        cmap: "viridis",
-        colors: [3, 4, 5, 6, 7, 3, 2, 4]
-      )
+      assert %Figure{axes: %{cmap: cmap}} =
+               [1, 2, 3, 4, 5, 6]
+               |> Matplotex.plot([1, 2, 3, 4, 5],
+                 cmap: "viridis",
+                 colors: [3, 4, 5, 6, 7, 3, 2, 4]
+               )
+
       assert is_list(cmap)
     end
   end