100 '
110 ' GWMA, a simple GW-BASIC illustration of the formula behind MA
120 '
130 KEY OFF:SCREEN 2:CLS
140 '
150 ' Give the variables some values...
160 '
170 A = -239                                             ' -1000 to + 1000
180 B = -.8                                              ' -2 to +2
190 C = 312.8                                            ' -1000 to +1000
200 D = 7.8                                              ' -12 to + 12
210 XSHRINK = 1: YSHRINK = .5                            ' Scale parameters
220 XOFS = 400: YOFS = 300                               ' Image centre point
230 '
240 ' Setup complete, now start the calculations
250 '
260 WHILE INKEY$ = ""
270    IF X < 0 THEN XS = -1 ELSE XS = 1                 ' These are the
280    XP = Y - ( XS * ( ABS ( B * X - C ) ) ) ^1 / D    ' important lines
290    YP = A - X                                        ' to use.
300    PSET ( (XP+XOFS)*XSHRINK, (YP+YOFS)*YSHRINK )
310    X = XP                                            ' Set new X
320    Y = YP                                            ' and new Y.
330 WEND
340 '
350 CLS                                                  ' If a key is pressed,
360 SCREEN 0                                             ' reset screen.