of <code>x</code>, and a stream to approximate <span class="katex"><span class="katex-mathml"><math><semantics><mrow><mi>π</mi><mtext>.</mtext></mrow><annotation encoding="application/x-tex">π\htmlClass{math-punctuation}{\text{.}}</annotation></semantics></math></span><span class="katex-html" aria-hidden="true"><span class="base"><span class="strut" style="height:0.43056em;vertical-align:0em;"></span><span class="mord mathnormal" style="margin-right:0.03588em;">π</span><span class="enclosing math-punctua