Polygonal Ridges in Gordii Dorsum (CTX Frame - Natural Colors; credits for the additional process. and color.: Dr Paolo C. Fienga - Lunexit Team)

This image from the Gordii Dorsum Region of Mars shows a large area covered with Polygonal Ridges in an almost geometric pattern.
The Ridges may have originally been Dunes which hardened (indurated) through the action of an unknown process.

Groundwater might have been involved.