icebergs :~)

Icebergs in Lake Winnipeg sometimes have stripes, formed by layers of snow that react to different conditions.

Blue stripes are often created when a crevice in the ice sheet fills up with melt water and freezes so quickly that no bubbles form.

Brown, black and yellow lines are caused by sediment, picked up when the ice sheet grinds downhill towards the lake.

When an iceberg falls into the lake, a layer of water can freeze to the underside. If this is rich in algae, it can form a green stripe. 

The one on the right is obviously for sale on eBay - it's even got a barcode :~)