dock_generator.erb

    <!--
      This is how this dock should look like:
    <% layout.each do |row| -%>
      <%= row -%>
    <% end %>
    -->
    <%- link_counter = 0 -%>
    <%- row_counter = 0 -%>
    <%- x_counter = 0 -%>
    <%- layout.each do |row| %>
    <!-- Row <%=row_counter %> -->
      <%- y_counter = 0 -%>
      <%- for j in 0..row.size - 1 -%>
        <%- c = row[j] -%>
        <%- if c == 'X' -%>
    <include>
      <name>dock_block_<%= link_counter %></name>
      <pose><%= x_counter %> <%= y_counter %> 0.25 0 0 0</pose>
      <uri>model://dock_block_4x4</uri>
    </include>
          <%- link_counter += 1 -%>
        <%- end -%>
        <%- y_counter += 2 -%>
      <%- end -%>
      <%- x_counter += 2 -%>
      <%- row_counter += 1 -%>
    <%- end %>