a reporter that takes a set of agents as input and reports the number of agents in the set
a built-in turtle or link variable that reports the color of the turtle or link
a command that: sets all the code-defined (not slider defined) global variables to zero clears the tick counter (leaving it with no value, not zero) kills all the turtles resets […]
a command that takes an agent or set of agents and a set of commands as input and makes each agent in the set (in random order) follow the commands
