function grafy3d
graphics_toolkit("gnuplot");
[x,y]=meshgrid(-15:0.4:15);
r=sqrt(x.^2+y.^2);
z=sin(r)./r;
figure(1)
surf(x,y,z)
print -djpg surf.jpg
figure(2)
pcolor(x,y,z);
shading("interp")
axis("square")
print -djpg pcolor.jpg
endfunction
