This example demonstrates a fork of D3 functions, showing how the enter, update, and exit selections manage SVG circle elements as data changes. Two buttons trigger transformations: "Remove" pops the last item from an array, while "Modify" uses a random splice to replace a data point. The code uses d3.select, scaleLinear, and the data join pattern with merge and exit methods, rendering steelblue circles that turn red when removed. The visualization is built with d3.v5 and SVG, with data defined as x/y coordinate pairs.