set title '2-D Interpolation Error Data, Order 3'

plot 'rms.out' u 1:3  t 'Resolution 1' w lp, \
     ''        u 1:7  t 'Resolution 2' w lp, \
     ''        u 1:11 t 'Resolution 3' w lp, \
     ''        u 1:15 t 'Resolution 4' w lp;