Date: Apr 13, 2013 8:36 PM
Author: David Park
Subject: Re: Arranging disks (or any object for that matter) be
Clif,

(This should replace my earlier posting so as to use Turtles instead of

Disks in the SetterBar heading.)

The previous Presentations solution can be easily modified for this.

<< Presentations`

I scale the turtle down so it can walk basically on a unit circle.

turtleShape = {Darker[Green], Thickness[1/32],

Circle[{-1, .7}, .5, {8 Pi/6, 3 Pi/2}],

EdgeForm[Directive[Thick, White]], Disk[{1, 0}, .5, {0, Pi}],

Disk[{0, 0}, 1, {0, Pi}], Disk[{-.5, 0}, .25, {Pi, 2 Pi}],

Disk[{.5, 0}, .25, {Pi, 2 Pi}], White, Disk[{1.2, .3}, .04]} //

ScaleOp[1/5, {0, 0}];

This provides the dynamic, again with a completely fixed background. Each

turtle is rotated and then translated into position. I added a circle as a

base for the turtles, who are arrayed clockwise about the circle.

DynamicModule[{numDisks = 0, angle = 0},

pagelet[

phrase["Number of Turtles:", Spacer[10],

SetterBar[

Dynamic[numDisks, (numDisks = #;

angle = -2 \[Pi]/Max[1, numDisks]) &], Range[0, 9]]],

Draw2D[

{{GrayLevel[0.5], ComplexCircle[0, 0.96]},

Dynamic@

Table[

turtleShape // RotateOp[(nn - 1) angle - \[Pi]/2, {0, 0}] //

TranslateOp[ToCoordinates[Exp[I (nn - 1) angle]]], {nn, 1,

numDisks}]},

PlotRange -> 1.5,

Background -> LightBrown,

ImageSize -> 500]

]

]

David Park

djmpark@comcast.net

http://home.comcast.net/~djmpark/index.html

From: Clif McInnis [mailto:c_mcinnis@hotmail.com]

Bob,

Thank you, that works very well. I am wondering if it is possible to put an

object in the place of the disk. I have a little turtle shape (the code

below)that I had tried to substitute for the line " Disk[{Cos[a], Sin[a]},

3/Max[8, n]]" which did not work out too well. My guess is that it would

work if I would assign the {x,y} values of the semi disk that makes the

shell to Cos[a],Sin[a] and then related the other parts of the shape to

those coordinates, however before I undertook that endeavor I thought that I

would just ask you to give me a yes/no answer as to whether it would even be

a possibility. Again Thank You for your help.

Sincerely -- Clifton McInnis

Graphics[{

Darker[Green], Thickness[1/32],

Circle[{-1, .7}, .5, {8 Pi/6, 3 Pi/2}],

EdgeForm[Directive[Thick, White]], Disk[{1, 0}, .5, {0, Pi}],

Disk[{0, 0}, 1, {0, Pi}], Disk[{-.5, 0}, .25, {Pi, 2 Pi}],

Disk[{.5, 0}, .25, {Pi, 2 Pi}], White, Disk[{1.2, .3}, .04]}]