The $N/6$ guard conjecture for integral orthogonal polygons

Let $P$ be an integral orthogonal polygon, meaning that all its edges have integer length, and let $N$ be its perimeter. The $N/6$ guard conjecture. The polygon $P$ can always be guarded with at most

$$\left\lfloor \frac{N}{6} \right\rfloor$$

guards. The best bound established in the paper is $\lfloor N/5\rfloor$, while the conjectured $N/6$ bound is motivated by integral versions of orthogonal comb polygons requiring $N/6$ guards and remains open.