Make your work to be in keeping with your purpose - Leonardo da Vinci

Блаженни са тези, които отварят ушите си за думите на мъртвите: трябва да се четат хубавите книги и да се вземат под внимание.

But leaves of yellowish green do not, when they reflect the atmosphere, create a reflection which verges on blue; for every object when seen in a mirror takes part in the color of this mirror; therefore the blue of the atmosphere reflected in the yellow of the leaf appears green, because blue and yellow mixed together form the most brilliant green, and therefore luster on light leaves which are yellowish in color will be a greenish yellow.

The function which the wing performs against the air when the air is motionless is the same as that of the air moved against the wings when these are without motion.