What is the significance of a clover-shaped flight track?
The flying looks too sloppy for a ground reference maneuver, a performance maneuver, or other required academic flying.  Given the concentration of the same flying in that same area and a review of the VFR sectional for the same area:  



This is probably some kind of training flight.  If it is for law enforcement, I'm not sure what is going on here.  One possibility is that it is a student practicing attitude instrument flying doing 'A' and 'B' patterns under the hood with an instructor - or at least trying to.



Another possibility is just standard flight training activities, periodically turning to avoid terrain or congested airspace in order to operate within these confines.