This example shows five blue rectangles positioned side by side in an SVG, with heights corresponding to an array of numbers (100, 250, 175, 60, 150). The rectangles are drawn on a baseline at the bottom of the viewport, creating a simple bar chart. The code uses D3 v4’s `selection.data()` and `selection.attr()` methods to bind the data and set each rectangle’s x, y, width, height, fill, and stroke attributes. The `height` variable is referenced but not explicitly defined, so the vertical placement relies on the SVG’s default coordinate system.