That’s a clever idea—color can really guide the eye and, if you plan the weight distribution with it, the piece will feel both cool and solid. Just make sure the lighter bricks are closer to the base; otherwise the whole thing might tilt like a loose cup. Try a gradient from dark at the top to lighter at the bottom, and see how the center of gravity settles. Good luck, and don’t forget to brace the base while you’re still assembling!