Introduction: Uncommon features have been observed in the cryptic region near the south polar cap during the spring time retreat of the seasonal cap. The defrosting of the seasonal CO2 cap leads to dalmatian spots named dark spots [1], spiders [2], fans [3] and polygonal crack patterns [4]. (Kieffer, 2007) proposed a semiquantitative model to explain all these processes. The dark spots, fans an...