EXERCISE 1: Escher Knitting Patterns
Please download the folder lab4_programs from the
download directory on cs111 server.
Escher used two basic patterns to produce an amazing variety of
patterns:
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A(red,blue,green,yellow,magenta)
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B(red,blue,green,yellow,magenta)
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Below are three practice knitting patterns to figure out. The
skeletons for the methods are in the LabKnitWorld.java
file.
Your Task
Fill in the code for these methods to obtain the patterns. Consult
Picture World contract
if necessary.
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labKnit1(Color.red, Color.green)
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labKnit2(Color.magenta, Color.blue)
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labKnit3(Color.blue, Color.red,
Color.cyan, Color.magenta)
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EXERCISE 2: Simple QuiltWorld Patterns
First, a gentle introduction to quilting (Tasks
2a & 2b):
Task 2a Suppose you are given the
following black box method:
public Picture triangle (Color
c)
Returns a Picture of a triangle of the specified Color whose
vertices are at (0,0), (1,0), and (0,1).
For example,
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triangle(Color.green);
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Using only the methods in the PictureWorld
contract, write (on paper) the expressions which will return the
following Pictures:
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picture 1
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picture 2
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picture 3
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Task 2b
Evaluate the following expressions. Draw (on paper) the
Picture that each represents. Indicate the colors in
whatever way is convenient (colored pencils, markers,etc.). Do
not write a program to run on the computer to show you the
pictures; do it by hand!
picture 4
overlay(clockwise90(triangle(Color.blue)),triangle(Color.blue));
picture 5
above(fourSame(flipDiagonally(triangle(Color.yellow))),
beside(triangle(Color.green),
above(empty(), flipVertically(triangle(Color.green)))));
Feel free to use local variables, to break the statement above to smaller,
more manageable ones. Here is one way of doing so:
Picture p1 = triangle(Color.green);
Picture p2 = flipVertically(p1);
Picture p3 = above(empty(), p2);
Picture p4 = beside(p1, p3);
Picture p5 = flipDiagonally(triangle(Color.yellow));
Picture p6 = fourSame(p5);
Picture p7 = above(p6, p4);
Task 2c
Read about QuiltWorld in
Problem Set 3.
Below are two quilt designs for you to figure out. The skeletons for the methods are in the
LabQuiltWorld.java file.
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