 
 # Here's a quick hack for switching traces on and off.
 
-trace = (s) -> #console.log s
+trace = (s) -> #console.log s()
 
 
 # ----

      else if x = seq([[a, b], [b, c], [c, a]]).find((e) => @third__.get(e)?]
        [f, g] = x
        h = @third__.get x
        trace "  Error in plus [#{@toSeq()?.join ', '}], (#{a}, #{b}, #{c})"
        throw new Error "Orientation mismatch."
      else
        triangles = @triangles__.plus tri a, b, c

    # edge `ab` lies in triangles `abc` and `bad`, then after the flip those
    # are replaced by new triangle `bcd` and `adc`.
    flip = (T, a, b) ->
      trace -> "flip [#{T.triangulation__.toSeq().join ', '}], #{a}, #{b}"
      c = T.third a, b
      d = T.third b, a
      children = seq [tri(b, c, d), tri(a, d, c)]
