because of the
    cost of evaluating the enormous offset curve expressions.
  </p>
    <h3>Byte compiling</h3>
    <p>
    The expressions for the X-spline tangent functions, even though they
    are "only" 65 lines of R code long, can be slow to evaluate.
    For this reason, the 'vwline' package has the 'ByteCompile' option
    set so that the package code is byte-compiled at installation to 
    improve performance.
  </p>
    <h2>
      <a name="summary">6. Summary</a>
    </h2>
    <p>
    This docume