This very special 'Standard Time' sundial (A Heliochronometer) is still under development.  The plate of this Equatorial Dial is made up of three rotatable rings.  The inner ring swings 15° (one hour) between fixed stops to make the annual adjustment for Daylight Saving.  The middle ring adjusts to allow for the distance east or west of the Time Zone centre.  When the outer date lines are matched against the inner ones then the hour and minute lines are rotated by exactly the right amount to synchronise Solar time and Clock time.  The rotating Alidade (sun-sight) and minute pointer are still to be added to the central spindle.