 the type of speckles every 4000 steps, non-equilibrium scheme.</span>

    <span class="c1"># Do the chemical modification, and change the spec-spec potential on the fly.</span>
    <span class="k">for</span> <span class="n">j</span> <span class="ow">in</span> <span class="n">np</span><span class="o">.</span><span class="n">random</span><span class="o">.</span><span class="n">randint</span><span class="p">(</span><span class="n">start_spec_index</span><span class="o">-</span><span class="mi">1</span><span 