When Do Toddlers Start Coloring In The Lines. It is one of the ways to practice hand - eye - brain coordination. Not all children reach a mile stone at the same time and i think its wrong to compare children.
He started coloring inside the lines at around. Well it depends on who the child is. But I can see that he is already doing it so thats good.
To encourage his learning show him.
This has to do with a combination of cognitive ability grip and fine motor control. Children who lack strength in their writing hand cannot draw and so cannot be creative. Improves Fine Motor Skills. Strength in the hand muscles is needed for drawing and writing.