Human subtlety will never devise an invention more beautiful, more simple or more direct than does Nature, because in her inventions nothing is lacki… - Leonardo da Vinci

Quelli che s’innamorano della pratica senza la scienza, sono come i nocchieri che entrano in naviglio senza timone o bussola, che mai hanno certezza dove si vadano. Sempre la pratica dev’essere edificata sopra la buona teorica, della quale la prospettiva è guida e porta, e senza questa nulla si fa bene.

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.

Practice must always be founded on sound theory.