By using Observable, the author of this post created an interactive bar chart that displays Taylor Swift's most-used words from her lyrics. The chart is made with D3.js and uses a dataset of Taylor Swift's lyrics to display the frequency of each word. The chart includes features such as hover-over tooltips, axis labels, and a title. The code for the chart is written in JavaScript and can be run in an Observable notebook or other text editor. The author also provides links to additional resources and datasets that can be used to build similar charts.