However, the drawing experts possibly knew that rectangles with relatively prime dimensions give one-line drawings. This idea is supported by the fact that of the 30 smallest relatively prime rectangular shapes, 75% appears among the documented drawings. It is further possible that they knew that if a square of a dot is added to a one-line lusona, the lusona would still be mono-linear. It seems clear that they had experimentally discovered this fact for 2 X 2 squares.
