Difficulties? err, its quite easy. Just have to becareful abt its proportions. And the features like eyes, nose and mouth is the most difficult parts.
The Pingpong ball activity.
Materials:
40 PingPong balls
color markers / acrylic paint
My favourite!
Difficulties? Its when i have no idea on what to draw onto the ppballs. And when the markers start to smurge. It ended up from dark color to light, and makes the ppball looks dull.