op'>=</span> <span class='ident'>test</span>::<span class='ident'>black_box</span>(<span class='number'>1000</span>);

    (<span class='number'>0</span>..<span class='ident'>n</span>).<span class='ident'>fold</span>(<span class='number'>0</span>, <span class='op'>|</span><span class='ident'>a</span>, <span class='ident'>b</span><span class='op'>|</span> <span class='ident'>a</span> <span class='op'>^</span> <span class='ident'>b</span>)
})</pre>

<!-- Neither of these read or modify the value, and are very