1 2 3 4 4 5 6 7 7 8 9 10 \begin{array}{:c:cc:c:} \hdashline 1 & 2 & 3 & 4\\ \hdashline 4 & 5 & 6 & 7\\ \hdashline 7 & 8 & 9 & 10 \end{array}