““But when you want to mark a number on an abacus, what do you do if there are no stones in a column? The number 60 is one wedge in the sixties column and no wedges in the ones column. How do you write “no wedges”? The Babylonians needed a placeholder that represented nothing. They had to, in effect, invent zero. And so they created a new character, with no value, to signify an empty column. They denoted it with two slanted wedges.””
![“Geometry, which should only obey Physics, when united with it sometimes commands it. If it happens that the question which we wish to examine is too complicated for all the elements to be able to enter into the analytical comparison we wish to make, we separate the more inconvenient [elements], we…” quote by Jean le Rond d'Alembert](https://sms4smile.com/quotes/img-quotes/0d9/jean-le-rond-d-alembert-26487_able_geometry-which-should-only-obey-physics_6945.jpg)
