a command takes an agent as input and turns the current agent towards that agent
a reporter that takes a turtle or patch as input and reports the distance between the current agent and the given turtle or patch.
a command moves the turtle backward a specified number of steps
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 stores the minimum x-coordinate for the world
a reporter that stores the minimum y-coordinate for the world
a built-in turtle reporter that stores the y-coordinate of the turtle
a reporter that stores the maximum y-coordinate for the world
