Functions Documentation 

Name 
random 
Syntax 
(random expression [number]) 
Argument List 
expression : A list or number.
number: The number you want to a random number between them the second must be greater than the first number. 
Returns 
expression: If the expression argument is a list it returns a random element of the list, if the expression is a number then returns a number between the expression number and optional number. 
Category 
random

Description 
If the expression argument is a list it returns a random element of the list, if the expression is a number then returns a number between the expression number and optional number. 
Example 
(random 1 10)
Can return any number between 1 and 10 like 3.
(random '(a b c d))
Can return any element in the list '(a b c d). 
Comment 
Very useful function for making variation in code. 