My high school students did this at the beginning of the school year and I thought it would be a good idea to share. I got this idea from the book called From Ordinary to Extraordinary: Art & Design Problem Solving by Ken Vieth.
This lesson is pictured on the cover of the book and discusses the transformation of something basic like a number 2 pencil. My students had to come up with an idea to draw something using only the shape/idea of a regular pencil. This was difficult for them to wrap their heads around at first, but once they got started, they come up with some pretty cool stuff.
Here are a few examples.
I am definitely going to use this idea again. I think it would also be interesting if students made a sculpture similar to these drawings with real pencils, cutting them and putting them together.