iner. In this case <code class="computeroutput"><span class="identifier">Box</span></code>
        objects will probably be created with <code class="computeroutput"><span class="identifier">geometry</span><span class="special">::</span><span class="identifier">envelope</span><span class="special">()</span></code> function. But to keep it simple lets just
        generate some boxes manually and insert them into the R-tree by using <code class="computeroutput"><span class="identifier">insert</span><span cla