This example visualizes surgical operation schedules for two patients in an ophthalmology clinic, showing planned and actual times for patient request, preparation, operation, and cleanup phases. The code extracts the operation type text from the data and displays it as plain text in a preformatted HTML element. It uses d3.v5, specifically the `select` and `range` functions from the d3 library, though the visualization primarily relies on basic DOM manipulation via `document.getElementById` rather than complex data binding or scales. The data comes from a static JavaScript array containing timestamped procedure phases.