I'm not sure what is meant by "color scheme" in this context. It seems to me that the way that term is used by laymen would make that an impossible assignment because of the infinite variety, but I'm sure I have that wrong! Anyway, what comes to mind is a values quilt, usually made with half square triangles, in mixtures of light, dark and medium. The emphasis is on bringing out a design by arranging the lighter and darker halves in various ways. If you google "values quilt" you'll get many examples.

The Dresden plate was my first thought, too. It's perfect for a traditional color wheel. A Chinese coins quilt might work, too. That's a very easy quilt to make.

Have you checked Christine Barnes' website? I had her for a color class several years ago and we made different blocks. She also sells patterns that demonstrate the different theories.

What about a convergence quilt? https://www.google.com/search?q=conv...e+q&aqs=chrome

I visited a website--that I can't find right now where her challenge was to make a block a month, that would each be a different color--She used a block format with a circle in the center. This large circle would be different --lets say aqua fabrics that were all mosaic(ed) with zig zag on a white square. So you could do each block in the same format the white background/grout. With the color in the circle being the part you were working on for your block of the week. Hope I made sense!
Another idea is actually not a block, it is a notebook. On one of the news letters I got recently the woman took classes on fine dress embellishment. They were all required to make a journal of their progress. She used a regular notebook with page protectors that could hold items, and class notes. It would tell how she did something (contained in the journal). Just think of how much better retention we would have of projects, and how to's if we didn't have to relearn something when we did it again!