Painting patterns and mandalas is fun. Especially after a busy day, painting patterns relaxes.
Just paint the stones in different colors. This creates beautiful color patterns.
Or paint a pattern into the stones. For example, this can be the flags of the different countries or small gift packages or just what you're thinking of.
Or you paint a circle and paint it. Paint your mandala. It doesn't have to look perfect or contain a lot of different shapes. The shapes and colors can be quite simple as here. Painting is just supposed to be fun.