Now for something completely different
A pyramid shaped rock has been found on Mars. In any place on Earth to find such a rock would be to have found an artifact, but on Mars it's just a rock, an unusual rock, but a rock.
Pyramid shaped rock found on Mars by NASA rover Curiosity | Space, Military and Medicine | News.com.au
When you find a symmetrical object it is usual to ask what could have shaped it, wind doesn't usually make things symmetrical and liquid tends to round things off and make them smooth.
Could it be this has been left there for us to find?