Creating a desktop, want 4 different shades of metal [South Dakota]

I am creating a desk, and I want the desktop to essentially look like butcher block (or a wood floor), but I want to create it with 1.5" strips of metal in 3 or 4 different shades. I'm wondering should I use different types of metal (tin, aluminum, etc). Or does someone have any suggestions on how I can use steel and use some sort of treatment to darken the strips to different shades. Thanks for any input!

You could use a combination like copper, brass, aluminum, stainless steel. Or, you could use aluminum which has been anodized and dyed. All colors are available - brass, copper, gold, green, blue, black, red, yellow, etc.