set term png
set out "Fig.oscillator.png"
set tics out
set xlabel "$t$"
set key bottom
set title "oscillator"
set axis x2 atzero
set x2format ""
plot \
 "oscillator.data.txt" using 1:2 with lines title "$\\theta(t)$"\
,"oscillator.data.txt" using 1:3 with lines title "$\\omega(t)$"