# very slow! be patient fx(a,x,n) = 0 < n ? fx(a,a*(1-x)*x,n-1): a*(1-x)*x unset key set samples 1600 set isosamples 100 set yrange [0:1] set xrange [2.5:4] set term pngc enh font "Arial,8" size 480,360 set out "logistic2.png" set xlabel "a" font ",10" set ylabel "x" font ",10" plot '++' using (xa = fx($1,0.8,100), $1):(fx($1,xa,int($2*100))) w d |