logothings
Turtles in a Circle
Seating turtles around a circle
My first challenge here was to figure out how to put turtles in a circle. I wanted them evenly spaced from the circle’s center and along its rim or perimeter. Here’s how I did it.
Dressing the Turtles Up
I wanted to have turtles in different costumes perched on the
perimeter of a circle. A red turtle was to remain in the center along
with a hidden ball. In the final project there were an assortment of
turtles [t2 t3 t12 t5 t6 t24 t10 t9 t1 t8 t24]. Two stayed in the
center (t2 and t24) and the rest (t3 t12 t5 t6 t24 t10 t9 t1 t8)
were to be placed on the perimeter. The red turtle, t2, was to remain
visible all the time. The ball, t24, was to remain in the center
hidden until the red turtle “threw” it.
To prepare, put all the turtles in the center.
ask [t2 t3 t12 t5 t6 t24 t10 t9 t1 t8 t24][cg pu]
Give each turtle its costume.
t24, ht setsh "soccerball t3, setsh "balloon t12, setsh "tree2 t5, setsh "helicopter4 t6, setsh "balloons t10, setsh "teddybear t9, setsh "teddypig t1, setsh "teddycat t8, setsh "teddydog
Now turn the job of putting the turtles in their respective places
over to another procedure. Notice the list does not include t2, the
red turtle, nor t24, the ball.
turtlecirc [t3 t12 t5 t6 t10 t9 t1 t8] end
to turtlecirc :turtlelist make "num count :turtlelist ask :turtlelist [cg] repeat :num [ask :turtlelist [rt 360 / :num] ask first :turtlelist [fd 100 setc random 256 ]make "turtlelist bf :turtlelist] end
I made turtlecirc more readable by creating a subprocedure for
handling all the instructions being repeated.
to turtlecirc :turtlelist make "num count :turtlelist ask :turtlelist [cg] repeat :num [tc.helper] end to tc.helper ask :turtlelist [rt 360 / :num] ask first :turtlelist [fd 100 setc random 256 ] make "turtlelist bf :turtlelist end
As I started using turtlecirc I changed it a bit. I gave turtlecirc an input so that I could setup the circle of turtles in different places on the screen.
to turtlecirc :turtlelist :position make "num count :turtlelist ask :turtlelist [setpos :position seth 0] repeat :num [tc.helper] end
Now I have turtles in a circle. I can do different things. My first project was a game in which a player controls the red turtle’s heading by using the left and right arrow keys. Then by pressing the space the player is asked how many steps the turtle takes. If the aim is good and the step estimate is good then the object on the circle changes shape. The player continues until all ring objects have changed.