Those who fall in love with practice without science are like a sailor who enters a ship without a helm or a compass, and who never can be certain whither he is going.
Leonardo da VinciWeight is caused by one element being situated in another; and it moves by the shortest line towards its centre, not by its own choice, not because the centre draws it to itself, but because the other intervening element cannot withstand it.
Leonardo da VinciIt's not enough that you believe what you see. You must also understand what you see.
Leonardo da Vinci