nx(x,y,a,b) = y + a*x - 5/(x**2+1) + 6 + 0.2*exp(-y**2)
ny(x,y,a,b) = -b*x

unset key
set size square
set samp 20000
set term pngcairo enh font ",6" size 720,480
set out "gumowski.png"

colors = "web-green web-blue orange dark-green steelblue dark-salmon"

set multiplot lay 2,3
do for [i= 1:3]{
a = -0.96 + (i-3)*0.49
b = 0.97
set title sprintf("a = %.3f, b = %.3f", a, b) font ",10" 
xp = yp = xc = yc = 0.1 
 plot '+' u (xc=nx(xp,yp,a,b), yc=ny(xp,yp,a,b), xc+yc):\
            (xp=xc, yp=yc, xc-yc) w d lc rgb word(colors,i)
}
do for [i= 4:6]{
a = -1.60 + (i-5)*0.19
b = 0.995
set title sprintf("a = %.3f, b = %.3f", a, b) font ",10" 
xp = yp = xc = yc = 0.1 
plot '+' u (xc=nx(xp,yp,a,b), yc=ny(xp,yp,a,b), xc+yc):\
            (xp=xc, yp=yc, xc-yc) w d lc rgb word(colors,i)
}
unset multiplot