a reporter that takes a set of agents as input and reports a random agent or takes a list as input and reports a random item from the list
a reporter that reports the set of agents that are patches
a keyword that takes a plural name and a singular name as input and defines a class of turtles with that name
a keyword that takes one or more variable names as input and defines a new global (cross-program) variable with each name
a command that takes a number as input and pauses all program activity for that number of seconds
a reporter that reports the set of all turtles
keywords that begin and end procedures
a command that advances the tick counter by one and updates all the plots