A part of a unit on Color Theory, students were challenged to create a color wheel in which their design, color mixing ability and craftsmanship were all important aspects of the piece. They could use only the primary colors (red, yellow and blue), along with white and black. They were required to include primary, secondary and tertiary colors, as well as tints. (Students could include shades in previous years, but I've found that this tends to dull their otherwise "jewel-like" paintings.)
Most students opted to do some sort of radial design, using a protractor to divide a circle into 30- or 60-degree segments. They painted their complex color wheels on 90# white sulphite paper, using acrylic paint.