Animated SVG rectangles appear in horizontal rows and grow to random heights and colors at regular intervals, then shrink and disappear. The visualization uses the d3 library’s `select`, `transition`, and `range` APIs to manage the lifecycle of each rectangle. Data is generated procedurally with JavaScript’s `setInterval` and `Math.random`, creating a constantly updating bar-like chart. The code defines a reusable `timePlot` function that handles enter, update, and exit states for smooth transitions.