ange the speckle types every 4000 steps as we mentioned in the previous
blocks.</p>
<div class="nbinput docutils container">
<div class="prompt highlight-none notranslate"><div class="highlight"><pre><span></span>[5]:
</pre></div>
</div>
<div class="input_area highlight-ipython3 notranslate"><div class="highlight"><pre><span></span><span class="c1">#model.save_system(&quot;model_before_simulation_0.xml&quot;)</span>

<span class="n">simulation</span> <span class="o">=</span> <span class="n">model</span><spa