kakels

I have a vision in my head, but I'm not experienced enough to put it on paper. I want to make squares and have them graduate from light to dark starting with the light in the center.

I want to find a collection that has colors going from an off white through grays and into dark gray or maybe a black. Stonehenge winter stone strips is a possibility. Then I want to applique something in a bright color on it. A flower maybe.

Anyone have any ideas where I can find a pattern idea? Or a color collection? I've been searching all day and can't find much.

Thanks in advance for any ideas