Leonardo da Vinci

Science is the captain, and practice the soldiers.

Experience is the sole interpreter of nature.

Necessity is the mistress and inventress of nature.

He who loves practice without theory is like the sailor who boards a ship without a rudder and compass and never knows where he may cast.

The human foot is a masterpiece of engineering and a work of art.

The greatest deception men suffer is from their own opinions.

Water is the driving force of all nature.

Nature never breaks her own laws.

To develop a complete mind: Study the art of science; Study the science of art. Learn how to see. Realize that everything connects to everything else.

The eye, which is called the window of the soul, is the principal means whereby the understanding can most completely and abundantly appreciate the infinite works of nature.

Simplicity is the ultimate sophistication.

Learning never exhausts the mind.

The noblest pleasure is the joy of understanding.

Iron rusts from disuse; stagnant water loses its purity and in cold weather becomes frozen; even so does inaction sap the vigor of the mind.

Obstacles cannot crush me; every obstacle yields to stern resolve.

As a well-spent day brings happy sleep, so a life well spent brings happy death.

The painter has the Universe in his mind and hands.

Art is never finished, only abandoned.

Where the spirit does not work with the hand, there is no art.

The mind of the painter must resemble a mirror, which always takes the colour of the object it reflects and is filled with as many images as there are objects placed before it.