# set terminal windows 
# set output
set pointsize 0.01
set title "Neutron Proton interaction for two different energy levels"
set xlabel "x"
set ylabel "y"
plot [x=(-0.8*640/480):(0.8*640/480)] [-.8:.8] "simpsonsdata.txt" every :::0::0 using 1:2 title "Path for Particle at E=25",  "simpsonsdata.txt" every :::1::1 using 1:2 title "Path for particle at E=-25"