a command that changes turtle’s mode to drawing lines (pen-down), removing lines (pen-erase), or neither (pen-up)
a value that indicates that no agent was found when using one-of, max-one-of, etc.
a reporter that takes a number as input and reports a random decimal number between the input number and zero (including zero but excluding the input number)
a reporter that takes two Boolean (true/false) inputs and reports true if either input reports true and reports false if both inputs report false
a reporter that takes some values as input and reports a single list containing all of those values
a built-in turtle reporter that stores the y-coordinate of the turtle
a reporter that takes a number as input and reports the square root of that number
a reporter that stores the maximum x-coordinate for the world