Octagon and tropical octagon yield braid invariants

In the present paper, we construct an invariant of braids in the real projective plane which corresponds to an ``action'' of braids on certain graphs in $\R{}P^{2}$ with labels. This paper is a sequel of papers \cite{M},\cite{KM}. It demonstrates once more that solutions to the octagon relation in various forms give rise to invariants of braids.