<span class="op">(</span>k <span class="op">=</span> <span class="va">k</span>, i <span class="op">=</span> <span class="va">i</span>, j <span class="op">=</span> <span class="va">j</span><span class="op">)</span><span class="op">)</span><span class="op">)</span></span></span>
<span class="r-in"><span><span class="fu"><a href="https://rdrr.io/r/graphics/abline.html" class="external-link">abline</a></span><span class="op">(</span>h <span class="op">=</span> <span class="fl">1</span> <span class="op">*</span>