For the majority of us, looks are the first thing we notice when assessing whether we want to flirt with someone. The flirt triangle is all about using your eyes to scan the faces of others. When we are in the company of strangers we look at their faces in a triangular fashion, starting with the eyes then moving down to the nose. With friends, this triangle moves even further down to the nose and mouth. When we feel in a flirty mood, the triangle expands out to capture the body. If someone stares intensely at your eyes or mouth for a split second longer than normal then it's a sure sign that they are attracted to you.