MCS-177 Project: Quilting

Due: Friday, September 20, at the beginning of class

MCS 177: Computer Science I, Fall 2002
Recommended preparation and schedule

Problem

In this project, you will use the basic quilting procedures introduced in section 1.3 to write more sophisticated procedures for constructing complicated quilts such as the Repeating Crosses pattern shown on page 15 of the text. Initially, some of the procedures you write will generate recursive processes, as described in chapter 2. Once you have well-written, working procedures, you will use techniques from chapter 3 to rewrite them so that they generate iterative processes instead.

Project Report

We will assign a specific audience and style for each project report; you should pay attention to these, because they will vary from project to project. In this first project report, you will pull together the code you wrote and the testing you did, in a concise but clear and organized fashion, for an audience already familiar with the project. As such, you need not tell a self-contained story. Instead, you should group the code and testing into logical sections, with a descriptive heading for each section and a clear caption on each procedure or set of test cases.

For this first project, we recommend you prepare your project report with DrScheme itself. Even though it isn't much of a word processor, it is adequate for a simple report like this, and using it will save you the hassles of cutting and pasting your code and images into a real word processor.. We have a separate document with tips on using DrScheme to write a report.

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

In lab

  1. Launch DrScheme. We recommend using the definition window for all of your definitions and using the interaction window only for quick experiments which you are unlikely to repeat. Save the program file early and often.

  2. To load into Scheme the definitions of the basic blocks, evaluate the following expression: 
        (load "~mc27/labs/quilting/quilting.scm")
    by typing the line into your definition window and hitting execute. Now you should be able to see each block by evaluating its name in the interaction window. In addition to the blocks mentioned in the book, we have also included two solid blocks, black-bb and white-bb. (On machines outside our lab, you will need to have installed the functional graphics tool, and then you can download quilting.scm and load it in.)

  3. The stack and quarter-turn-right procedures are built into our Scheme. Try them out as in exercise 1.8 on page 16 of the text, and make sure you understand what each does and how combinations behave. (We should point out here that the code from the book is available from the web page http://www.gustavus.edu/~max/concabs/code/ ; simply follow the link for the chapter you want. Using these files will substantially reduce your typing.) Note that names such as rcross-bb continue to name the same, unmodified basic block throughout. The procedures give you back transformed copies of the image rather than changing the original image in any way.

  4. Do exercise 1.9 on pages 16-17. (We'll bring the card-stock basic blocks to lab to help you think these through.)

    Be sure to save your definition window early and often. (Just click the Save button.) Note that the next time you use DrScheme, you can simply open this file by using the File menu.

  5. Do exercise 1.10 (page 17).

  6. Read the paragraph at the beginning of section 2.4 and do exercise 2.13 (page 40).

  7. Do exercise 2.14 (page 40).

  8. Read the paragraphs after exercise 2.14 and do exercise 2.15 (page 42). Note: be sure to carefully read the paragraph preceding exercise 2.15 before starting to program.

  9. Do exercise 3.3 (page 54).

If you have time

  1. Produce your own basic blocks; see exercise 1.11 on pages 17-18. (Sorry, we don't have any way of providing graphical input to Scheme.)

  2. You may find other interesting ways to replicate images beyond pinwheeling and checkerboarding. For example, you could combine rotated versions of a basic block, some of which have been inverted and others not. You might also try using the built-in procedure mirror-image. Be creative!