TO followMouse ask-concurrent turtles [ if mouse-down? [ set heading towardsxy mouse-xcor mouse-ycor fd 0.1 ] ] END ;; Requires the button to be set to Forever (checkbox) and the button to be in Observer mode. The button would have followMouse as its command. ca cro 32 fd 12 or fd 21 pd Then try out the button and drag with your left mouse button held down to see the turtles follow your mouse pointer. TO colorRed ;; to make the mouse "draw" in red: if mouse-down? [ ask patch mouse-xcor mouse-ycor [ set pcolor red ] ] END