global 0 t {x=x0;y=y0}
x0'=x0
y0'=y0
fx=a*x*(1-x)
fy=a*y*(1-y)
x'=c*fy+(1-c)*fx
y'=c*fx+(1-c)*fy
par a=3.5,c=0
aux d=abs(x-y)
aux cp=c
aux ap=a
init x0=.82
@ total=100,trans=99.9,maxstor=100000
@ meth=discrete
@ xp=y0,yp=cp,xlo=0,xhi=1,ylo=0,yhi=.2
done

Initial conditions 2 para
range y0 from 0 to 1 in 100 steps
range c from 0 to 0.2 in 50 steps
Reset storage=n
Crv or array  2

when it is done

Graphics Edit
change line-type to -1

then Numerics Colorcode Another-quantity
 choose D  and then optimize

escape
restore

(This code remembers the initial data you chose)