Wherever good fortune enters, envy lays siege to the place and attacks it; and when it departs, sorrow and repentance remain behind.

To lie is vile, to tell truth is excellent, if not noble.

Those who, in debate, appeal to their qualifications, argue from memory, not from understanding.

The first object of the painter is to make a flat plane appear as a body in relief and projecting from that plane

Human subtlety will never devise an invention more beautiful, more simple or more direct than does nature because in her inventions nothing is lacking, and nothing is superfluous.

average human “looks without seeing, listens without hearing, touches without feeling, eats without tasting, moves without physical awareness, inhales without awareness of odour or fragrance, and talks without thinking.

Therefore, O students, study mathematics and do not build without foundations.