1   REM Arthur model with spatial representation on the screen
10  SCREEN 1: WINDOW (0, 0)-(320, 240): CLS

50  AR = .8: BR = .2
60  SA = .2: BS = .8
70  NA = 1: NB = 1
80  S = .01: R = .01
90  RANDOMIZE TIMER

100  DO
110    y = INT(RND * 240)                         ' draw random case
120    x = INT(RND * 320)

180     IF RND < .5 GOTO 200

190        RETURNA = AR + R * NA: RETURNB = BR + R * NB: GOTO 210
200        RETURNA = SA + S * NA: RETURNB = BS + S * NB
210          IF RETURNA > RETURNB THEN NA = NA + 1 ELSE NB = NB + 1
220          IF RETURNA > RETURNB GOTO 250 ELSE GOTO 260

250       PSET (x, y), 1: GOTO 300
260       PSET (x, y), 2

300 LOOP WHILE INKEY$ = ""
310 END