RailwayRouteOptimization/scripts/Block/CreateBlock/doc/CreateBlock_proc_en.html

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  <ol>
    <li>Select the entities you want to use for the new block.</li>
    <li>Specify the reference point of the block.</li>
    <li>Enter a name for the new block in the dialog that is shown and click
    OK.</li>
  </ol>
  <p>The block is now added to the block list and instances of it can be
  inserted into the drawing. The entities you have selected in the first step
  are removed and replaced by a block reference of the newly created block.</p>
</div>