Q-Tips. Pointillism, grade, Dots upon dots, circles upon circles, maybe do color families . I like the idea of breaking this into sections for each child to complete and then putting the whole thing back together (LS)
How To Make DIY Painted Rocks - 30 Tutorials and Inspirational Diagrams. Click the link under each tutorial diagram for full information. Elspeth McLean ( McLean) paints ocean rocks with thousands of tiny dots.
Hundertwasser Inspirations - after lessons on line, pattern, color choice and filling spaces w/ color. A medium-hard project just that demands a high degree of manual dexterity and arm/hand strength for bold, smooth color.