OPEN "PULSE.DAT" FOR OUTPUT AS #1
WIDTH #1, 255
PRINT #1, "T", "Q", "C", "DQ", "DC", "M"
10 REM IBM: PULSE  (Pulse and Recycle)
20 CLS
30 SCREEN 1, 0: COLOR 15, 0
40 LINE (0, 0)-(319, 180), 3, B
50 E = 1
60 Q = 2
70 C = 2
80 TM = 200
90 K1 = .02
100 K2 = .01
110 K3 = .0003
120 K4 = .2
130 F1 = .05
140 F2 = .1
150 Q0 = 1
160 C0 = 1
170 TX = 160
180 T0 = 320 / TX
190 DT = .5
200 M = TM - F1 * Q - F2 * C
210 DQ = K1 * E * M - K2 * Q - K3 * C * C * Q
220 DC = K2 * Q + K3 * Q * C * C - K4 * C
230 Q = Q + DQ * DT
240 C = C + DC * DT
250  PSET (T * T0, 180 - Q * Q0), 1
260  PSET (T * T0, 180 - C * C0), 2
270 T = T + DT
280  IF T * T0 < 319 GOTO 200
285 LOCATE 2, 2: PRINT "Pulse.bas"
290 SLEEP: SLEEP
300 END