Cyclical data example

Some data has an associated period that should be taken into account for visualizations. For instance, patterns may repeat according to a certain pattern based on the hour of the day, day of the week, month of the year, etc., or according to some non-calendar-based timeline.

We should make an example of plotting such data, first for a fixed, known timebase, and then possibly for exploring possible timebases interactively (akin to Fourier analysis, i.e. plotting across a range of periodicities).

Tasks:

- [ ] Select suitable dataset (e.g. NYC Taxi, for calendar-based periods)
- [ ] Make or update notebook showing how to fold the data across periods
- [ ] Make an example showing how to search the space of possible periods to discover temporal patterns

See also #104.

No file, test, or entry point is named. Start by reviewing related issue #104 and selecting a suitable periodic dataset, then plan a notebook for folding data across known periods and a separate exploration of possible periods; done means both examples demonstrate the requested temporal patterns.

Written by the indexing model from the issue text.