Take a look at Bruce&#39;s customised symbol sets on the wiki. I based mine on those. I have not tried adding a completely new symbol to therion yet, but here is how I override the pebbles area fill with one which looks more like I prefer. Include this layout in your pdf export command to see pebbles rendered with this custom style:<div>
<br></div><div><div>layout CustomisedSymbols</div><div>  code metapost</div><div><br></div><div><span class="" style="white-space:pre">	</span>beginpattern(pattern_pebbles);</div><div><span class="" style="white-space:pre">		</span>pickup PenC;</div>
<div><span class="" style="white-space:pre">		</span>path qq;</div><div><span class="" style="white-space:pre">		</span>for i=0.0u step 0.6u until 5.1u:</div><div><span class="" style="white-space:pre">			</span>for j=0.0u step 0.6u until 5.1u:</div>
<div><span class="" style="white-space:pre">			</span>  qq := (superellipse((.05u,0),(0,.05u),(-.05u,0),(0,.-.05u),.75))</div><div><span class="" style="white-space:pre">				</span> randomized (u/45)</div><div><span class="" style="white-space:pre">				</span> scaled (uniformdeviate(1.2)+.55)</div>
<div><span class="" style="white-space:pre">				</span> rotated uniformdeviate(360) </div><div><span class="" style="white-space:pre">				</span> shifted ((i,j) randomized 0.55u);</div><div><span class="" style="white-space:pre">			</span>   draw qq;</div>
<div><span class="" style="white-space:pre">			</span>endfor;</div><div><span class="" style="white-space:pre">		</span>endfor;</div><div><span class="" style="white-space:pre">		</span>patternstep(5.1u,5.1u);</div><div><span class="" style="white-space:pre">	</span>endpattern;</div>
<div><br></div><div><span class="" style="white-space:pre">	</span>def a_pebbles (expr p) =</div><div><span class="" style="white-space:pre">		</span>T:=identity;</div><div><span class="" style="white-space:pre">		</span>thfill p withpattern pattern_pebbles;</div>
<div><span class="" style="white-space:pre">	</span>enddef;</div><div><br></div><div>  endcode<br></div><div>endlayout CustomisedSymbols</div></div><div class="gmail_extra"><br><br><div class="gmail_quote">On 16 November 2012 09:28, Dave Clucas <span dir="ltr">&lt;<a href="mailto:dave@daveclucas.com" target="_blank">dave@daveclucas.com</a>&gt;</span> wrote:<br>
<blockquote class="gmail_quote" style="margin:0 0 0 .8ex;border-left:1px #ccc solid;padding-left:1ex">In Mulu many of the passages are part filled with sandstone pebbles. I&#39;d like to create a user area and a user symbol based on pebbles where the ellipses are filled with a colour (light brown). Can anybody tell me how to modify the standard definition?<br>

<br>
Dave Clucas<br>
<a href="mailto:dave@daveclucas.com" target="_blank">dave@daveclucas.com</a><br>
<a href="http://daveclucas.com" target="_blank">http://daveclucas.com</a><br>
<a href="http://mycaves.org" target="_blank">http://mycaves.org</a><br>
<br>
<br>
<br>
______________________________<u></u>_________________<br>
Therion mailing list<br>
<a href="mailto:Therion@speleo.sk" target="_blank">Therion@speleo.sk</a><br>
<a href="http://mailman.speleo.sk/mailman/listinfo/therion" target="_blank">http://mailman.speleo.sk/<u></u>mailman/listinfo/therion</a><br>
</blockquote></div><br></div>