Date: 1637

"Now a painter cannot represent all the different sides of a solid body equally well on his flat canvas, and so he chooses one of the principal ones, sets it facing the light, and shades the others so as to make them stand out only when viewed from the perspective of the chosen side. In just the ...

— Descartes, René (1596-1650)

Date: 1686, 1689, 1697

"'Tis so many times in the capacities of Youth: they who can receive any impression like the Virgin-wax, will as easily suffer a defacement unless it be hardned and matur'd by Time: whereas others who are hard to be wrought upon like Steel, retain the Images which are Engraven on them with much m...

— Nourse, Timothy (c.1636–1699)