'----------------------- Insect1 ------------------

BackColor 30

CLS

ForeColor 33

Num=1100

a = 50

BackColor 33

CLS

x=1

y=2

FOR i = 1 TO Num

ForeColor 2*i+1

PSET(400+ .6*x,280+.3*y)

xx = x + a*(x-y)/(x*y)

yy = SGN(y)*(x - y)

x= xx

y= yy

NEXT i

FOR k=1 TO 10^6

NEXT k