
Fans gather at three points on the vertical axis, at the top, the centre and the bottom, and two triangles open from them inside a set of concentric circles. Behind the circle, a faint grid of horizontal and vertical lines crosses the sheet. The plotter drew everything, in pen, pencil and ballpoint; nothing is drawn by hand.
One of four Meridian drawings. All four are built on a circle of evenly spaced points: chords between the points form a star polygon, and fans of lines gather at points on the vertical axis.