We know they exist on Mars, we can see them from orbit. It would be great to get a lander image of them from the ground.

Pyramids seem to be one of the commonest erosion formations on Mars, very distinctive and found almost everywhere. For example, large parts of the Valles Marineris and other chaos regions are filled with them chock-a-block.

Arsinoes Chaos

Here is something about Sagan's Pyramids, c. 1972 (published in Cosmos 1980):

http://mars-news.de/mr9/4205-78.html"

I once thought they might be surface expressions of underlying crystalline structure, rather than strictly speaking ventifacts caused by wind action. The cold and the action of ice in the near-vacuum of the atmosphere must have something to do with their formation, I thought.

The little bitty pyramids in the rlb2 image have some interesting debris around them suggesting mechanisms of formation that include the action of ice. Perhaps its explosive sublimation. Note the little rock piles at the base of the closer pyramid. The possibility of explosive action forming pyramids and other things first occurred to me when I saw some apparent pingos in northern Utopia (I think). Their south-facing sides had been literally blown open, the debris scattered on the ground below, the interior (presumably ice) exposed to the atmosphere. Of course I can't find the images now!

In addition to the pyramidal formations, there are almost perfectly rectangular slabs in many surface images going back to the Vikings (also in Pathfinder images). These various angular shapes are a special characteristic of Mars.

Cheers,