Interactive image hotspots in p5.js with tack.

We&rsquo;re going to build a small interactive p5.js sketch around a pixel-art steam locomotive. Click the brass whistle and it toots. Click the cab door and a friendly engineer appears, waving. Click the smokestack and a puff of pixel smoke drifts up out of the funnel. The point of the exercise isn&rsquo;t really the train. It&rsquo;s that p5.js gives you a fantastic playground for responding to…