I was thinking about electric circuits in general, so very much including transistors. I mean, we were also talking about street networks in general, or were we excluding intersections?<p>The simple example I was thinking about is a &quot;digital potentiometer&quot;. Think about the audio output of your motherboard, which&#x27;s amplification you can control digitally.<p>Kirkhoff&#x27;s circuit laws are extremely simplifying.<p>An interesting exercise would be to prove the statement we were talking about in the fictional world of &quot;Kirkhoff circuits&quot;.