Post Light

Cheap garden lights abound, but they usually have small solar cells and wimpy LEDS.
Here is a design that uses a larger solar cell in a tilted peak that stays cleaner. A 2000 mah AA nimh cell can last through several cloudy days. A high intensity LED with color of your choosing can personalize the light. 4x4 posts are not that well controlled for size, so tweak the OpenSCAD parameters to match your posts before printing. Or, print them a little smaller and trim down the post tops on two sides.