If you take as your pattern the wings of feathered birds, these are more powerful in structure of bone and sinew because they are penetrable, that is… - Leonardo da Vinci

Ask counsel of him who rules himself well.

All objects transmit their image to the eye in pyramids, and the nearer to the eye these pyramids are intersected the smaller will the image appear of the objects which cause them.

Up Lake Como towards Germany is the Chavenna Valley where the River Mera enters the lake. Here are barren and very high mountains with large rocks ... In these mountains the water birds called maragon. Here are born firs, larches and pines, fallow deer, ibexes, chamois and terrible bears. It cannot be mounted except by walking on all fours. There go the mountain men in snowy weather with great ingenuity to bring the bears down the mountains. These narrow mountains have the river in between. They are left and right for a space of 20 miles all like this.