a simple shelf i made for my shop, similar design to my bathroom shelf, but for a plain wall. 

Very simple to print, no supports, and it only requires about 35grs of filament. Prints quite easy and thick layers can be used, as they don't affect the model quality. Voronoi bottom allows for great resistance, but also water drainage if needed, and it reduces print time significantly. 

Final measure is 20 x 9 x 4,5 cms