Rectangle divisions, a triangle in a semicircle, paired numbers
Sketchy geometric figures with line segments and looped numeral pairs such as 4-8 and 5-10
This leaf carries a cluster of quickly drawn geometric figures: a canceled horizontal rectangle split into upright rectangles, a triangle inscribed in a semicircle whose altitude is carried down to form a rectangle beneath the diameter, and several line segments dotted with points. Below them, pairs of numbers are joined by looping strokes of the pen, drawn in the ordinary (non-specular) left-to-right sense. The numeral pairs 4 with 8 and 5 with 10 express doublings, while 40 is set against 40. Fainter figures and show-through from adjacent leaves are also present.
On this page
Canceled rectangle divided into upright strips
A horizontal rectangle is subdivided by verticals into narrower upright rectangles and then struck through with the pen. Nearby, another small rectangle rests on a single line segment that is itself divided into two parts.
Triangle inscribed in a semicircle over a rectangle
A triangle is set inside a semicircle, its apex on the arc and its base on the diameter. The triangle's height is continued downward to become one side of a rectangle drawn beneath the diameter, with a short line segment marked by three points below.
Paired numbers joined by looping pen-strokes
Pairs of numerals are tied together by curved strokes of the pen: 4 with 8 and 5 with 10, each pair a doubling, and 40 set against 40. The marks are written in the non-specular sense rather than in Leonardo's usual mirror script.