e consuming because it must make a lot of operations; 
the computing time is also related with the number of grid points.
</p>
<pre class="example">(%i1) load(fractals)$
(%i2) plot3d (mandelbrot_set, [x, -2.5, 1], [y, -1.5, 1.5],
                [gnuplot_preamble, &quot;set view map&quot;],
                [gnuplot_pm3d, true],
                [grid, 150, 150])$
</pre></dd></dl>

<dl>
<dt><u>Function:</u> <b>julia_set</b><i> (<var>x</var>, <var>y</var>)</i>
<a name="IDX2174"></a>
</dt>
<dd><p>Julia sets.
</