Eight hundred years ago, builders of cathedrals wanted walls made of light. Glassmakers cooked colored glass, cut it into pieces, and held them together with strips of lead — so when the sun came through, the whole story lit up. Most people couldn't read; the windows were their books.
Your canvas is divided by dark lead lines, like a real window. Fill each glass piece with deep jewel colors — the brush makes them glow. Different colors in neighboring pieces make the window sing.