This example links a donut chart and a bar chart to visualize the distribution of vowels, consonants, and punctuation in user-submitted text. Users enter text in a textarea and click “Submit text” to generate the charts. Hovering over a donut segment highlights it and displays the corresponding character count in the linked bar chart. The code uses d3.pie for the donut layout, d3.arc for the ring geometry, and SVG event handlers for interaction.