165 DIVIDE CIRCUMFERENCES AND DRAW PARALLEL LINES AS INDICATED. TAKE THE DIAGONALS OF SIX IN SIX DIVISIONS, AND THE REST FOLLOWS.
166 DESCRIBE CIRCUMFERENCES EQUAL AND TANGENT, AND TAKE THE DIAGONALS OF FOUR IN FOUR DIVISIONS; THEN IN THE CONCENTRIC CIRCUMFERENCES TAKE THE DIAGONALS OF SIX IN SIX DIVISIONS.
