ef="a-stairway-to-heaven.html#stairway-to-heaven"><i class="fa fa-check"></i><b>3.2</b> Stairway to heaven</a></li>
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<li class="chapter" data-level="4" data-path="building-a-rainbow.html"><a href="building-a-rainbow.html"><i class="fa fa-check"></i><b>4</b> Building a rainbow</a><ul>
<li class="chapter" data-level="4.1" data-path="building-a-rainbow.html"><a href="building-a-rainbow.html#build-rainbow-with-r-graphics"><i class="fa fa-check"></i><b>4.1</b> Build rainbow with R graphics</a></li>
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