This example demonstrates a D3 workshop exercise focused on SVGs and transitions, showing how to create and animate rectangles within an SVG canvas. It begins with a static scene of blue, red, and yellow shapes, then uses D3’s `transition()` and `attr()` methods to move rectangles to random positions over one second when a button is clicked. The code appends rectangles bound to an array of color data, merges existing selections, and animates both position and fill color randomly. It relies on D3 v4’s data join and selection APIs, with animations driven by `duration()` and `delay()` methods.