This is a great project to use a ruler, teach a little about 3-D and form.
Just start with a plain white piece of paper. Draw a center dot. Have them draw 3-5 shapes around the center dot. (I usually recommend circles, square, trianges, rectangles, hearts or diamonds)
Then, show them how to use a ruler and connect the edges of the shape to the center dot. Any edge that you lay your ruler down and it cuts through the shape means DON'T draw the line!
Once you show them on the board, they will fully understand.
You can add stripes and designs to your shapes like mine. We use marker to color them in. Then, have the students cut out the entire design and post onto a background colored paper that compliments the art piece.
This is a great one-day project, and they love the result...and so do I!