{

  (pages): {
    ./linked-image.html
    ./linked-stylesheet.html
  }
  ...pages/

  /*
    spread the final result of this closure into the parent tree.
  */
  ...{
    links:  Tree.map(pages, getLinkedFilesFromHtml.js)
      → (links) => Tree.flat(links, 2) → (a) => [...new Set(a)]

    //linksAsTree is a nested object representation of the paths.
    //can use that object as a mask on all to get a 'filtered' tree.
    linksAsTree: pathsToObjs.js(links)
    onlyLinkedFiles: Tree.mask(<.>, linksAsTree)
  }.onlyLinkedFiles

  index.html: page.ori.html(Origami.mdHtml(Origami.inline(README.md)))

}