<p>Polygon patterns on the tundra develop from yearly freeze-thaw cycles. Wedges of ice that extend vertically into the ground develop geometric shapes due to the crystal structure of the ice.
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Aerial view of polygon patterns on tundra
<a rel="nofollow" class="external text" href="https://www.flickr.com/people/41585865@N06">Western Arctic National Parklands</a>
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<a rel="nofollow" class="external text" href="https://www.flickr.com/photos/nps_wear/9903655363/">Patterned Ground</a>