This example visualizes the Iris Dataset with an animated scatter plot that lets users switch both axes independently via dropdown menus. The visualization supports both quantitative and categorical variables, using D3 scales and transitions to smoothly animate circle positions and axis updates over 2 seconds. The chart is built with reusable D3 functions `scatterPlot` and `menu`, rendering SVG elements with `scaleLinear`, `scalePoint`, `axisLeft`, and `axisBottom` for the axes and controls.