I have just returned from a long vacation where I did
not have Internet access for two weeks. Thanks for checking this blog in the
interim.

*inquisitive programming*.

Lately, I’ve been
exploring cellular automatons. My Langton’s Ant Scratch project is an example of a cellular automaton. Langton’s ant
moves on a square grid according to a simple rule and is a two-dimensional,
two-color, cellular automaton (CA).

*Computer Recreation*s column in

*Scientific American*magazine and has authored several books about the joys of computer programming.

In his column,

To view my scratch project that codes Dewdney’s tur-mite,
click on this link.*Two-dimensional Turing machines and tur-mites make tracks on a plane*, found in the September 1989 issue of Scientific American, he discusses a multi-colored tur-mite I call Dewdney’s tur-mite.
http://scratch.mit.edu/projects/40908756/

I am also working on a Scratch project that implements
Wolfram’s (of

*Mathematica*fame) rule L90, one-dimensional cellular automaton. When the one-dimensional iterations of rule L90 are successively stacked, the Sierpinski triangle pattern is produced. The single operator in the code is an XOR logic gate. Scratch has AND, OR, and NOT logic operators but not an XOR operator. The XOR operator eXcludes the case when the two inputs to the OR operator are 1 (true). In other words, XOR (1,1) = 0.
I’ve gotten as far on this project as creating the
XOR operator in Scratch. To view the XOR gate, click on this link.

http://scratch.mit.edu/projects/popswilson/3270654

I will soon
have a PDF file that describes the math and programming techniques for both
Langton’s Ant and Dewdney’s Tur-mite ready for distribution upon request.
I will post
the complete rule L90 project when it has been completed.