The history of mathematics is a history of human curiosity and ingenuity.
Over the centuries the Indians developed sign language for communicating phenomena of interest. Programmers from different tribes (FORTRAN, LISP, ALGOL, SNOBOL, etc.) could use one that doesn't require them to carry a blackboard on their ponies.
出自先秦《荀子·性恶》引古语。不知儿子的为人,看看他的朋友就清楚了;不知国君是否贤明,看看他左右的大臣是什么德行就知道了。