Neither do we like to admit that the pleasures of knowledge, though more elevating, are not more lasting than other pleasures, and are almost equally dependent on the accidents of our bodily state (Introduction to Philebus).
2.

The number of the interval which separates the king from the tyrant, and royal from tyrannical pleasures, is 729, the cube of 9.

Which Plato characteristically designates as a number concerned with human life, because NEARLY equivalent to the number of days and nights in the year.

He is desirous of proclaiming that the interval between them is immeasurable, and invents a formula to give expression to his idea.
Those who spoke of justice as a cube, of virtue as an art of measuring (Prot.), saw no inappropriateness in conceiving the soul under the figure of a line, or the pleasure of the tyrant as separated from the pleasure of the king by the numerical interval of 729.

And in modern times we sometimes use metaphorically what Plato employed as a philosophical formula.