Turn the Shutters

How to play

1. Shutters have four positions: Closed (0), Ajar (1), Open (2), and Inverted (3).
2. Tapping a shutter advances itself and its direct side neighbours by one step.
3. Positions are indicated by slat angles and small corner pips (0 to 3).
4. Close all nine shutters (all position 0) in 16 presses or fewer to win.

About

A 3x3 grid of shutters in four positions. Tapping any shutter advances it and its adjacent neighbours by one rotation. Find the shortest path to close every shutter in 16 presses or fewer.