This example animates a line chart of population projections, showing how individual series grow, decline, and change direction over time. Using D3 v3 with SVG and animation, it draws multiple lines simultaneously and animates them by manipulating the `stroke-dasharray` and `stroke-dashoffset` SVG properties. The dataset, loaded from a CSV file, contains 28 different population projection scenarios for each year from 2012 to 2031, with the animation revealing each line progressively to illustrate trends. The `animateLines` function demonstrates a technique for animating lines by transitioning dash properties, which is particularly useful for highlighting growth, decline, or geographical movement in time-series data.