Agfdhyk

I don't know how to plot diagram like a "#", anyone could give some tips?

Thank you!

Welcome to TeX.SE! Can one draw such a graph? Sure. Are people here willing to do that for you? Well this will depend on their mood and also how new you are. Believe me, it is much more fun to do it on your own. Note also that there are 3d packages and nonlinear transformations etc. which can do a much better job if you have a concrete scenario and want more than just a cartoon.

documentclass[tikz,border=3.14mm]{standalone}

usetikzlibrary{intersections}

defldarray{{"i","i+1"}}

defluarray{{"k","k+mu","k+1"}}

begin{document}

begin{tikzpicture}

foreach X in {1,2,3}

{draw[name path global=hor-X-0] (0.1*X,2*X) to[bend left=12] ++ (5,1);}

foreach X in {1,2}

{draw[name path global=vert-X-0] (2*X-0.5,1+0.1*X) to[bend left=15] ++ (0.3,7);}

foreach X [count=XX starting from 0] in {1,2,3}

{foreach Y [count=YY starting from 0] in {1,2}

{pgfmathsetmacro{ld}{ldarray[YY]}

pgfmathsetmacro{lu}{luarray[XX]}

path[name intersections={of=hor-X-0 and vert-Y-0,by=pXY}] (pXY)

node[circle,fill,inner sep=2pt,label=below right:$g_{ld}^{lu}$]{};}}

end{tikzpicture}

end{document}

Follow marmot's sample,

Notice usetikzlibrary{intersections} and in the following code, define $Y= {1,2}$ is the Horizontal line, and $X={1,2,3}$ is the vert...

begin{center}

begin{tikzpicture}

foreach X in {1,2,3}

{draw[name path global=hor-X-0] (0.1*X,2*X) to[bend left=12] ++ (5,1);}

foreach X in {1,2}

{draw[name path global=vert-X-0] (2*X-0.5,1+0.1*X) to[bend left=15] ++ (0.3,7);}

foreach X in {1,2,3}

{foreach Y in {1,2}

    {ifnumY=1

        defly{i}

        else

        defly{i+1}

        fi

        ifnumX=1

        defld{k} 

        else

        ifnumX=2

        defld{k+mu}

        else

        defld{k+1}

        fi

        fi

        path[name intersections={of=hor-X-0 and vert-Y-0,by=pXY}] (pXY)

        node[circle,fill,inner sep=2pt,label=below right:$g_{ly}^{ld}$]{};}}

end{tikzpicture}

end{center}