a keyword that takes one or more variable names as input and defines a new global (cross-program) variable with each name
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
a command that takes an x-coordinate and a y-coordinate as input and sets the x-coordinate and y-coordinate of the turtle to these values, respectively
a command that takes a variable and a value as input and sets the value of the variable to the inputted value
a command that takes a number as input and turns the turtle right that number of degrees
a command that resets the tick counter to zero, sets up all plots, then updates all plots