Luckily How to create a heatmap doughnut chart could be used to layout both the scheme and its ramp.
Using Doughnut chart to show color ramps
Using the previous techniques and libraries described in Ramping color swatches, Looking up color table, Alternative schemes, and Playing around with colors in VBA it becomes more or less a one liner to create the chart below – which shows the label sections, their underlying colors and a circular ramp between them
Multiple column ramps
The code for creating the diagram above using the libraries in the cDataSet.xlsm workbook is published earlier on this page