10 REM IBM: FACTORS  (Model of external  limiting factors)
20 CLS
30 SCREEN 1, 0: COLOR 15, 0
35 LINE (0, 0)-(319, 180), 0, BF
40 LINE (0, 0)-(319, 180), 2, B
50 J = 5
60 I = 1
70 Z = 2
80 K1 = .08
90 K2 = .05
100 K3 = .01
110 DI = 2
120 N = J / (1 + K3 * I)
130 P = K1 * I * N
140 I = I + DI
150 PSET (I / Z, 180 - P), 1
160  IF (I / Z) < 319 GOTO 120
163 LOCATE 2, 2: PRINT "Factors.bas"
165 SLEEP: SLEEP: END
170 J = J + 5
180 I = 0
190  IF J < 25 GOTO 120