set-current-plot
a command that takes a plot name as input and makes that plot the current plot
set-default-shape
a command that takes a type of agent and a shape as input and sets the default shape for new agents of that type to the specified shape
pen-down, pen-erase, pen-up
a command that changes turtle’s mode to drawing lines (pen-down), removing lines (pen-erase), or neither (pen-up)