Farkas Bolyai quotes:

When the time is ripe for certain things, these things appear in different places in the manner of violets coming to light in the early spring.

Detest it [a certain difficult mathematics problem] just as much as lewd intercourse; it can deprive you of all your leisure, your health, your rest, and the whole happiness of your life.

Detest it as lewd intercourse, it can deprive you of all your leisure, your health, your rest, and the whole happiness of your life. Having himself spent a lifetime unsuccessfully trying to prove Euclid's postulate that parallel lines do not meet, Farkas discouraged his son János from any further attempt.

The mathematical giant [Gauss], who from his lofty heights embraces in one view the stars and the abysses ...

Do not try the parallels in that way: I know that way all along. I have measured that bottomless night, and all the light and all the joy of my life went out there.