Eleven circles arranged along a horizontal line demonstrate the `d3.scaleSequential` API with a rainbow interpolator. Each circle’s horizontal position is mapped by a linear scale from data values 0 to 100 to pixel coordinates, while its fill color uses the sequential scale’s domain to sample `d3.interpolateRainbow`. The circles render as SVG elements via a data join, with D3 v7 handling the DOM updates. The example contrasts continuous positioning with continuous color mapping, showing how two scales can drive different visual channels from the same dataset.