ass="n">key</span><span class="p">,</span> <span class="n">freq</span><span class="p">,</span> <span class="n">amp</span><span class="p">,</span> <span class="n">phase</span><span class="p">)</span>
        <span class="n">tide</span> <span class="o">+=</span> <span class="n">FLOW_SCALE</span><span class="o">*</span><span class="n">amp</span><span class="o">*</span><span class="n">np</span><span class="o">.</span><span class="n">cos</span><span class="p">(</span><span class="n">freq</span><span class="o">*<