This construction to trisect a line segment comes from Proofs Without Words by Scott Coble, via this page. The code looks like this:

      scene
      .point(width/7*3, height/3)
      .point(width/7*5, height/3)
      .segment(0,1)
      .circle(0,1)
      .circle(1,0)
      .line(0,2)
      .segment(0,3)
      .segment(4,1)
      .segment(2,6)
    

Also check out this one.