(* Content-type: application/mathematica *)

(*** Wolfram Notebook File ***)
(* http://www.wolfram.com/nb *)

(* CreatedBy='Mathematica 6.0' *)

(*CacheID: 234*)
(* Internal cache information:
NotebookFileLineBreakTest
NotebookFileLineBreakTest
NotebookDataPosition[       145,          7]
NotebookDataLength[      5542,        140]
NotebookOptionsPosition[      5148,        122]
NotebookOutlinePosition[      5486,        137]
CellTagsIndexPosition[      5443,        134]
WindowFrame->Normal
ContainsDynamic->True *)

(* Beginning of Notebook Content *)
Notebook[{

Cell[CellGroupData[{
Cell["Project - Brick Wall Illusion", "Section",
 CellChangeTimes->{
  3.4612562964071407`*^9, 3.461682317732991*^9, {3.461963778667519*^9, 
   3.461963782196739*^9}, {3.46196449800065*^9, 3.4619645004331207`*^9}}],

Cell["\<\
The \"brick wall\" below exhibits a relatively newly discovered optical \
illusion. The lines of cement between the bricks seem to converge or diverge \
where you are not looking. The strength of the effect depends critically on \
the geometry of the wall. \
\>", "Text",
 CellChangeTimes->{{3.461963791901847*^9, 3.461964026537462*^9}, {
   3.462109620357394*^9, 3.46210968342418*^9}, 3.4621097152891903`*^9}],

Cell[BoxData[
 TagBox[
  StyleBox[
   DynamicModuleBox[{$CellContext`a$$ = 
    0.6900000000000001, $CellContext`cc$$ = 0.065, $CellContext`ss$$ = 0.68, 
    Typeset`show$$ = True, Typeset`bookmarkList$$ = {}, 
    Typeset`bookmarkMode$$ = "Menu", Typeset`animator$$, Typeset`animvar$$ = 
    1, Typeset`name$$ = "\"untitled\"", Typeset`specs$$ = {{{
       Hold[$CellContext`a$$], 0.6}, 0.5, 1}, {{
       Hold[$CellContext`ss$$], 0.3}, 0, 1}, {{
       Hold[$CellContext`cc$$], 0.06}, 0, 0.3}}, Typeset`size$$ = {
    600., {163., 167.}}, Typeset`update$$ = 0, Typeset`initDone$$, 
    Typeset`skipInitDone$$ = True, $CellContext`a$90$$ = 
    0, $CellContext`ss$91$$ = 0, $CellContext`cc$92$$ = 0}, 
    DynamicBox[Manipulate`ManipulateBoxes[
     1, StandardForm, 
      "Variables" :> {$CellContext`a$$ = 0.6, $CellContext`cc$$ = 
        0.06, $CellContext`ss$$ = 0.3}, "ControllerVariables" :> {
        Hold[$CellContext`a$$, $CellContext`a$90$$, 0], 
        Hold[$CellContext`ss$$, $CellContext`ss$91$$, 0], 
        Hold[$CellContext`cc$$, $CellContext`cc$92$$, 0]}, 
      "OtherVariables" :> {
       Typeset`show$$, Typeset`bookmarkList$$, Typeset`bookmarkMode$$, 
        Typeset`animator$$, Typeset`animvar$$, Typeset`name$$, 
        Typeset`specs$$, Typeset`size$$, Typeset`update$$, Typeset`initDone$$,
         Typeset`skipInitDone$$}, 
      "Body" :> ($CellContext`b = 
        1; $CellContext`c = $CellContext`a$$ + $CellContext`cc$$; \
$CellContext`s = $CellContext`ss$$ (-1)^$CellContext`j; $CellContext`t = 
        Table[
          
          Rectangle[{(
              2 $CellContext`i) $CellContext`b + $CellContext`s, \
$CellContext`c $CellContext`j}, {(
              2 $CellContext`i) $CellContext`b + $CellContext`b + \
$CellContext`s, $CellContext`c $CellContext`j + $CellContext`a$$}], \
{$CellContext`i, 0, 10}, {$CellContext`j, 0, 15}]; $CellContext`l = Table[
          
          Rectangle[{0, $CellContext`c $CellContext`j + $CellContext`a$$}, {
           22 $CellContext`b, $CellContext`c $CellContext`j + \
$CellContext`c}], {$CellContext`j, 0, 15}]; 
       Graphics[{Gray, $CellContext`l, Black, $CellContext`t}, AspectRatio -> 
         Automatic, ImageSize -> 600]), 
      "Specifications" :> {{{$CellContext`a$$, 0.6}, 0.5, 
         1}, {{$CellContext`ss$$, 0.3}, 0, 1}, {{$CellContext`cc$$, 0.06}, 0, 
         0.3}}, "Options" :> {}, "DefaultOptions" :> {}],
     ImageSizeCache->{642., {234.375, 239.625}},
     SingleEvaluation->True],
    Deinitialization:>None,
    DynamicModuleValues:>{},
    SynchronousInitialization->True,
    UnsavedVariables:>{Typeset`initDone$$},
    UntrackedVariables:>{Typeset`size$$}], "Manipulate",
   Deployed->True,
   StripOnInput->False],
  Manipulate`InterpretManipulate[1]]], "Output",
 CellChangeTimes->{{3.461957310772806*^9, 3.461957313929472*^9}, 
   3.461957362939788*^9, {3.461957405401208*^9, 3.461957418733654*^9}, {
   3.461957774349724*^9, 3.4619578483543873`*^9}, 3.4619579243756866`*^9, 
   3.461963607546506*^9}],

Cell[TextData[{
 "This ",
 StyleBox["Manipulate", "Input"],
 " allows one to vary some of these geometric parameters to see how they \
change the illusion. ",
 StyleBox["a", "Input"],
 " is the height of the bricks, ",
 StyleBox["ss", "Input"],
 " is a parameter that determines the horizontal offset from one row to the \
next; and ",
 StyleBox["cc", "Input"],
 " controls the thickness of the cement between the rows. The project is to \
define a similar ",
 StyleBox["Manipulate", "Input"],
 " including a few more parameters that can be controlled. I was told, for \
example, that the ",
 StyleBox["GrayLevel", "Input"],
 " of the cement is important - that would be something to vary. I wonder \
what happens if the bricks and cement are colored?"
}], "Text",
 CellChangeTimes->{{3.4619640493377857`*^9, 3.461964194171774*^9}, {
  3.46196428594133*^9, 3.4619644789004583`*^9}}]
}, Open  ]]
},
WindowSize->{1002, 816},
WindowMargins->{{228, Automatic}, {Automatic, 0}},
FrontEndVersion->"6.0 for Mac OS X x86 (32-bit) (April 20, 2007)",
StyleDefinitions->"Default.nb"
]
(* End of Notebook Content *)

(* Internal cache information *)
(*CellTagsOutline
CellTagsIndex->{}
*)
(*CellTagsIndex
CellTagsIndex->{}
*)
(*NotebookFileOutline
Notebook[{
Cell[CellGroupData[{
Cell[590, 23, 214, 3, 67, "Section"],
Cell[807, 28, 420, 7, 41, "Text"],
Cell[1230, 37, 3017, 59, 492, "Output"],
Cell[4250, 98, 882, 21, 71, "Text"]
}, Open  ]]
}
]
*)

(* End of internal cache information *)