How many theorems in geometry which have seemed at first impracticable are in time successfully worked out!
Mathematics reveals its secrets only to those who approach it with pure love, for its own beauty.
Give me but a firm spot on which to stand, and I shall move the earth.
Give me a place to stand, and a lever long enough, and I will move the world.
The centre of gravity of any cylinder is the point of bisection of the axis.
The centre of gravity of any parallelogram lies on the straight line joining the middle points of opposite sides.