The same 272 Old Faithful observations can be viewed cumulatively.
One npudist() call selects bandwidths optimized for the joint-distribution target and estimates the probability at or below each eruption-duration and waiting-time pair.
This object is estimated directly, not by integrating the density.
It opens in RStudio's Viewer, where you can rotate, zoom, and resize the surface.
Find the full script in Gallery Video Demos.