A perfect circle touching a plane at a single point
An almost infinite weight moved by an almost infinite smallness of force
Under the heading 'the greatest ease of motion', a circle rests on a horizontal line with two weights suspended below it. Leonardo argues that if the line p q is a perfect plane and the circle a b d perfectly round, their contact must be a single point, on which the circular body rests with balanced weight. From this he concludes that an almost infinite magnitude of weight could be moved by an almost infinite smallness of force, as the lines a b and c d demonstrate over the line p q.
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Point contact of circle and plane
If p q is a perfect plane and the circle a b d of perfect roundness, their contact is at a single point, upon which the circular body rests with equal weight. From this, an almost infinite weight could be moved by an almost infinite smallness of force, as shown by the lines a b and c d over p q.