A single-axis scatterplot shows one user's hourly step counts and total intensity across Tuesday hours for one week, using ECharts 5.3.2. Each point’s x-position is the hour, and the symbol size encodes step total. The chart filters a CSV dataset of Fitbit activity to a hard-coded user ID and date range, then maps intensity values to point size. Data is loaded via `fetch` and parsed manually, with chart configuration built from `title`, `singleAxis`, and `series` arrays.