Page 337 - J. C. Turner - History and Science of Knots

Crochet Work-History and Computer Applications 327

different angles between the handle and the hook, detachable or `Swiss-Army'
style needles to allow several hooks to be used with the same handle, hooks in
a variety of materials (bone, wood, plastic, metal, ... ), needles with variously
shaped thumb rests, and so forth. There is even a special prosthetic device
available that allows one-armed crocheters to continue to enjoy their hobby!
[11]

Crochet and computing

In computing, researchers generally build an understanding of complex ideas
by first selecting a narrow problem or application and developing methods
specific to it. With that small problem solved, the researcher looks for ways to
generalize the solutions to cover larger classes of problems. At the University
of Waikato (Hamilton, New Zealand), members of the Computer Science de-
partment have been using crocheting as a sample application to explore issues
in the automation of creative design and image storage and retrieval.
With the construction of the CADD (Computer Aided Doily Design) sys-
tem, we examined the formal rule or grammar systems have been used in the
visual and musical arts to support creativity [5]. By making explicit the gen-
erally implicit rules for forming a piece, insight is gained into the fundamental
structures of the art form itself. These knowledge-based systems provide a de-
scription of the art form that can be tested for validity, and that can be used
to generate new instances of that art form. We demonstrated this technique
by developing a program that uses a rule and grammar description of crochet
lace to automatically generate new lace patterns.
Specifically, our model incorporates the following levels of description:

1) Simple constructive constraints: These constraints describe the pos-
sible ways in which individual crochet stitches may be connected to each
other. For example, a double crochet may connect to another stitch at
its base or its cap, but not by the middle of the double crochet.
2) Geometric constraints: As the crochet lace is designed, a graphical
pattern for it is simultaneously drawn on the screen. The geometric
properties of the graphical display provide guidance in achieving validity
for the pattern that CADD is creating. As an example, given that CADD
is attempting to place two double crochet stitches beside each other, the
distance between the caps of the stitches may indicate that a joining
chain is needed. This physical distance also determines the number of
chain stitches necessary for the join. The geometric model also supports
the achievement of symmetry in the pattern, an important concept in
crochet lace.