Hello, peeps!

I've recently found some odd symbols under the Whiterun main gate bridge. There is also another one on the right dragon-figure outside Jorrvaskr. The bridge symbol is an equilateral triangle with a circle inside, and the Jorrvaskr one has the circle 'half-in-half-out' of the triangle.
Anyone have clues or theories? Or more locations of these symbols?

k. bai.

Those are called Shadowmarks. They are related to the Thieves Guild, there's a book at their base that explains their meaning.

its the all-seeing eye..!!!

They are shadowmarks to help or warn thieves. The mark outside of Jorvaskaar for example warns thieves that it is very dangreous to steal from there.

The first one by the mai bridge means Safe, and the Jorrvasker mark means Danger.
The Theives Guild is a crafty bunch.