Them heavey stationary easels are nice - but relatively easy.
Now if you have to make it light enough to carry around, fold
up to fit under the bed when not in use, fit on a table top,
stand up AND become a table (water color very wet washes),
things get more interesting.
Posted this before but here's the url to my Transformer/Go-Bot
Water Color Easel. The second version of this easel took only
a quarter of the time spent doing the first one.
If you want to give your trig and geometry skills a real work
out make one of these puppies. And the wedged mortise and tenons,
the sliding dovetails etc. will use some of your special skills.
AND, you can use up some of those precious scraps you've been