2dwaves(CAM-PC)

2次元格子上のセルートマトン。ルールは少々複雑だが、4つの四角形が弾力的な伸び縮みを繰り返しながら次第に有機的なパターンに変わっていく様子が興味深い。時間的にリバーシブルなので、6000ステップで反転させて初期状態に復帰させている。全体で約12000ステップにおよぶ長大な状態遷移である。

\ 2DWAVES.EXP 2d generalization of STRINGS.EXP 18Mar89nhm
This experiment generalizes the technique used in STRINGS.EXP
to achieve harmonic waves. The rule used here employs a
checkerboard updating: on even time steps, we update the even
sites on the lattice, and at odd times the odd sites.
We use 8 states at each lattice site: the most significant 2
bits come from CAM-A, while the least significant bit is simply
the parity of a site's position (x+y), and is gotten from
plane 2 (this plane contains a checkerboard, and doesn't change
with time). In plane 3 we mark the sublattice that is currently
being updated---this plane contains an alternating checkerboard.
The rule is simply this: if all 4 neighbors of a cell being
updated have the same value, then the given cell is incremented
by twice the difference of its value and the neighbor value, mod
4. Unlike STRINGS.EXP this rule is very nonlinear, and even for
the contrived initial state provided, macroscopic waves decay.

\ 2D generalization of STRINGS.EXP 19Mar89nhm
( Based on an experiment written by Hrgovcic Hervoje )

NEW-EXPERIMENT N/VONN &/HV
: H+V &HORZ &VERT XOR DUP >PLN2 >PLN3 ; MAKE-TABLE H+V STEP

N/VONN &/CENTERS
: +DELTA &CENTER CENTERS PAIR &CENTER 1 XOR NORTHS PAIR - + ;
: 4SAME NORTHS SOUTHS = EASTS WESTS = NORTHS EASTS = AND AND ;

: WAVES CENTERS 4SAME &CENTER' 0<> AND IF +DELTA THEN >PLNA
CENTER >PLN2 CENTER' NOT >PLN3 ;

MAKE-TABLE WAVES OPEN-PATTERN 2DSIN.PAT 0 2 FILE>IMAGE

: Reverse -STEP# 3 NOT-PL ; ALIAS R