Two more unusually shaped rock formations have been discovered on the surface of the Red Planet.
Thanks to the plethora of high quality images returned by NASA's rovers, Mars has become a prime example of how the brain can be tricked in to interpreting an otherwise abstract pattern as something of significance - a phenomenon known as pareidolia.
The first of the two most recent finds is a rock formation that looks a bit like a set of traffic lights. It consists of a tall stone with several small stones spaced vertically up the side of it.
"I saw this one and I thought 'hang on, that looks a bit strange,'" said space video journalist Joe Smith who first came across the object. "I posted it on the internet and people said they thought it looked like a set of traffic lights too - although some people did say it looked like a totem pole."
The second object, a perfectly spherical rock, was found a few days earlier by NASA themselves. Scientists explained that the ball was likely to have been formed by repeated compacting and hardening - a process known as concretion.