MCS-177 Project: Fractal Curves

Due: Wednesday, April 6, at the beginning of class

Recommended preparation and schedule


In this project, you will experiment with tree recursion by looking at fractal curves. Complete the project and its report individually (not with partners).

Computer Exercises

Work through all the exercises of section 4.3 in the text. See below for notes particularly about exercises 4.7 and 4.8.

One technical tip: if you can't see a fractal with fine details clearly because it is too small, you can enlarge the image in Scheme by using the resize-image procedure, which is built-in to our Scheme. For example,

 (resize-image (line 0 0 1 1) 400)
would give you an image of a line from the center of the image to the upper-right corner, but it would be much larger than usual.

Rather than typing in the definition of c-curve, you can click on the following file in Netscape and save it somewhere in your home directory: ~mc27/labs/fractal-curves/c-curve.scm

Regarding exercise 4.7: The examples in the book all involve c-curves between the points (0,-1/2) and (0,1/2), with just the level varying. You should also do some examples with other end points. Your goal should be to determine a formula L(dn) for the length of a level-n C-curve between two points distance d apart. (In the book's examples, d is always 1. Your extra examples should vary this.) You need not mathematically prove that your formula always holds, though we'll provide extra credit for those who do.

Regarding exercise 4.8: You should have fun designing your own fractal. You can also design more than one new fractal. If you do so, they need not all be of the form described in exercise 4.8 (paths with detours). Some could be more like Sierpinksi's gasket than like c-curves, for example.

Project Report

You should simply turn in a DrScheme printout that shows your procedures and the tests you did, including the images that resulted from the tests. For exercise 4.7, you can give your formula for L(dn) in a text box, or you may find it easier to write it in by hand. Be sure to group your work into logically related sections and put a descriptive heading at the beginning of each section. Your audience for this report consists of people already familiar with this assignment.

To get some sense of how this project report will be graded, look at the grading sheet that we use.

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