Here is a fun art project we did using lines. One of the moms of our group suggested this.
First, trace your hand with pencil, and then draw straight lines across the page and curvy lines over the hands. Then use a pattern of colored markers to accentuate the lines.
It was a little tedious for the 4 and 5 year old, and I told them to take a break if they started to get sloppy. Vincent hasn't finished his yet.
Eva: 4 years
Sophia did her foot: age 7
Gianna: age 12
And Gianna has been working on her pencil drawings, too: