HiRISE source color JP2 image file of Mars north polar dunes in active alteration by season. ESP_016032_2600 at HiRISE catalog search index. Upper right shows a 'leaf' shape or paisley pattern which repeats regularly along the dune crests at dark streaking and dark spots, with gullies. Also appears at some non-dark spots in the dune ripple patterns. Some liquid type drainage erosion apparently at the lower left marked, originating at the dark shaded dune crest where light and shadow meet. More at www.marsroverblog.com , danajohnson0 topics. 04/2010