diff --git a/lib/eqrcode/svg.ex b/lib/eqrcode/svg.ex
index 2ed5ea4..2ea64ab 100644
--- a/lib/eqrcode/svg.ex
+++ b/lib/eqrcode/svg.ex
@@ -94,38 +94,70 @@ defmodule EQRCode.SVG do
     |> Enum.to_list()
   end
 
-  defp substitute(data, row_num, col_num, svg_options)
+  defp substitute(data, row_num, col_num, %{module_size: module_size})
        when is_nil(data) or data == 0 do
-    y = col_num * svg_options[:module_size]
-    x = row_num * svg_options[:module_size]
+    %{}
+    |> Map.put(:height, module_size)
+    |> Map.put(:style, "fill: transparent;")
+    |> Map.put(:width, module_size)
+    |> Map.put(:x, row_num * module_size)
+    |> Map.put(:y, col_num * module_size)
+    |> draw_rect
+  end
+
+  # This pattern match ensures that the QR Codes positional markers are drawn 
+  # as rectangles, regardless of the shape
+  defp substitute(1, row_num, col_num, %{color: color, module_size: module_size, size: size})
+       when (row_num <= 8 and col_num <= 8) or
+              (row_num >= size - 9 and col_num <= 8) or
+              (row_num <= 8 and col_num >= size - 9) do
+    %{}
+    |> Map.put(:height, module_size)
+    |> Map.put(:style, "fill:#{color};")
+    |> Map.put(:width, module_size)
+    |> Map.put(:x, col_num * module_size)
+    |> Map.put(:y, row_num * module_size)
+    |> draw_rect
+  end
 
-    ~s(<rect width="#{svg_options[:module_size]}" height="#{svg_options[:module_size]}" x="#{x}" y="#{
-      y
-    }" style="fill:transparent"/>)
+  defp substitute(1, row_num, col_num, %{
+         color: color,
+         module_size: module_size,
+         shape: "circle"
+       }) do
+    radius = module_size / 2.0
+
+    %{}
+    |> Map.put(:cx, row_num * module_size + radius)
+    |> Map.put(:cy, col_num * module_size + radius)
+    |> Map.put(:r, radius)
+    |> Map.put(:style, "fill:#{color};")
+    |> draw_circle
   end
 
-  defp substitute(1, row_num, col_num, %{shape: "circle", size: size} = svg_options) do
-    y = col_num * svg_options[:module_size]
-    x = row_num * svg_options[:module_size]
-
-    if (row_num <= 8 && col_num <= 8) || (row_num >= size - 9 && col_num <= 8) ||
-         (row_num <= 8 && col_num >= size - 9) do
-      ~s(<rect width="#{svg_options[:module_size]}" height="#{svg_options[:module_size]}" x="#{x}" y="#{
-        y
-      }" style="fill:#{svg_options[:color]}"/>)
-    else
-      ~s(<circle r="#{svg_options[:module_size] / 2.0}" cx="#{x + svg_options[:module_size] / 2.0}" cy="#{
-        y + svg_options[:module_size] / 2.0
-      }" style="fill:#{svg_options[:color]};"/>)
-    end
+  defp substitute(1, row_num, col_num, %{color: color, module_size: module_size}) do
+    %{}
+    |> Map.put(:height, module_size)
+    |> Map.put(:style, "fill:#{color};")
+    |> Map.put(:width, module_size)
+    |> Map.put(:x, row_num * module_size)
+    |> Map.put(:y, col_num * module_size)
+    |> draw_rect
   end
 
-  defp substitute(1, row_num, col_num, svg_options) do
-    y = col_num * svg_options[:module_size]
-    x = row_num * svg_options[:module_size]
+  defp draw_rect(attribute_map) do
+    attributes = get_attributes(attribute_map)
+    ~s(<rect #{attributes}/>)
+  end
+
+  defp draw_circle(attribute_map) do
+    attributes = get_attributes(attribute_map)
+    ~s(<circle #{attributes}/>)
+  end
 
-    ~s(<rect width="#{svg_options[:module_size]}" height="#{svg_options[:module_size]}" x="#{x}" y="#{
-      y
-    }" style="fill:#{svg_options[:color]}"/>)
+  defp get_attributes(attribute_map) do
+    attribute_map
+    |> Enum.map(fn {key, value} -> ~s(#{key}="#{value}") end)
+    |> Enum.join(" ")
   end
 end