Symmetric versus one-sided motion of the cords
When equal cord shifts leave the weight unchanged
Leonardo distinguishes two cases of the suspended rod. When both cords are moved equally toward the rod's centre, they keep their original equal share of the weight; but when only one cord moves inward and the other stays fixed at its end, every degree of motion changes the weight distribution. Three long horizontal rod diagrams accompany the text, and the closing rule states that the remaining weights on the cords relate as the opposite spaces enclosed between the rod's centre and the two cords.
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Equal inward motion of both cords leaves the load unchanged
A rod suspended at its ends apportions its weight equally to the two cords. Even though the cords are moved equally toward the centre of the rod, they do not change their original weight. The diagram is marked 2 2.
One-sided motion changes the weight at every degree
But if one cord is moved toward the centre of the rod while the other stays fixed at its end, every degree of motion produces a variation of weight between them. This is the asymmetric counterpart to the balanced case above.
Remaining weights as the opposite spaces on the rod
The remainder of the weights on the cords will have together the same proportion as the opposite spaces enclosed between the centre of the rod and the two cords. This applies to the rod unequally divided between the cords.