an apt conformity between the symbol and what it represents

Sometimes, as Recorde himself noted about his equals sign,there's an apt conformity between the symbol and what it represents.Another example of that is the plus sign for addition,which originated from a condensing of the Latin word et meaning and.Sometimes, however, the choice of symbol is more arbitrary,such as when a mathematician named Christian Kramp introduced the exclamation mark for factorials just because he needed a shorthand for expressions like this.