Making .m compatible with Octave

I don't have a Matlab license, so I only tested on Octave.

On Octave I got this error:
error: surface: z and c must have same size
error: called from:
error:   /usr/share/octave/3.2.4/m/plot/surface.m at line 85, column 7
error:   /usr/share/octave/3.2.4/m/plot/surface.m at line 51, column 5
error:   /usr/share/octave/3.2.4/m/plot/surf.m at line 47, column 5
error:   $BOHME/eye_draw.m at line 55, column 6
error:   eye1.m at line 42, column 1