tree.psvg

<!-- tree.psvg                                           -->
<!-- A port of https://processing.org/examples/tree.html -->
<psvg width="640" height="360">

  <def-branch h="0">
    <asgn h="{h*0.66}"/>
    <if true="{h>2}">
      <push>
        <rotate rad="{theta}"/>
        <line x1="0" y1="0" x2="0" y2="{-h}"/>
        <translate x="0" y="{-h}"/>
        <branch h="{h}"/>
      </push>
      <push>
        <rotate rad="{-theta}"/>
        <line x1="0" y1="0" x2="0" y2="{-h}"/>
        <translate x="0" y="{-h}"/>
        <branch h="{h}"/>
      </push>
    </if>
  </def-branch>

  <var theta="{PI/6}"/>

  <translate x="{WIDTH/2}" y="{HEIGHT}"/>

  <stroke color="black" cap="round"/>
  <line x1="0" y1="0" x2="0" y2="-120"/>
  <translate x="0" y="-120"/>
  <branch h="120"/>

</psvg>