Equal proportionality of various kinds
Red-chalk note on inverted and direct order in proportion
In red chalk Leonardo writes that 'equal proportionality can be of various kinds' and works the point through several sets of numbers. He contrasts an arrangement marked 'eversa' (overturned) with one in 'direct order', pairing terms such as 6:8, 9:3 and 12:4 and setting the descending column 12, 6, 3 against 8, 4, 2. The figures are grouped within bracketed proportion diagrams.
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Inverted versus direct order
Leonardo states that 'equal proportionality can be of various kinds.' He shows the same relation first 'eversa' (overturned or inverted) and then in 'direct order', juxtaposing the columns 12, 6, 3 with 8, 4, 2 so that the proportion holds whichever way it is read.