Did your children ever ask you what THEY could do with your iPhone? Well, here is something to keep them busy while you are, for instance, driving a car, ride a bus, wait at the physicians, etc. They can combine different dolls with different dresses, coats, shoes, and hats. Color pens colorize their dolls in a variety of colors.
They can draw with sharp or wide pens and observe the outcome when drawing with different levels of transparency.
Oups, the pic needs correction? Just select the white pen and white out everything that should not be there. Still not satisfied? Use the eraser and let the artist start over again.
Of course, once a doll is nicely colorized, they can store it in the photo app. So later you can help the proud artist to mail it to grandpa (He has an email address, hasn't he? Otherwise it's about time he gets one!).