plate1[L_,d_]:=Graphics[{LightGray,EdgeForm[{Thick,Black}],Polygon[{{-d,-5L},{-d,5L},{-d+5(Sqrt[2])L,10L},{-d+5(Sqrt[2])L,0}}]}]

plate2[L_,d_]:=Graphics[{LightGray,EdgeForm[{Thick,Black}],Polygon[{{d,-5L},{d,5L},{d+5(Sqrt[2])L,10L},{d+5(Sqrt[2])L,0}}]}]

color[10]=Red;color[9]=Orange ;color[8]=Yellow;color[7]=Green;
color[6]=Blue;color[5]=Purple;color[4]=color[3]=color[2]=Black;

wave[x1_,x2_,y_,n_]:=Plot[y+Sin[n π (x-x1)/(x2-x1)],{x,x1,x2},Filling->y,FillingStyle->color[n],PlotRange->{{x1,x2},{-15,20}},Axes->False]

waves1[L_,d_]:={wave[-15,-.9d+2L,-3L,8],wave[-15,-.9d+3L,-L,9],wave[-15,-.9d+3L,L,5],wave[-15,-.9d+3L,3L,7],wave[-15,-.9d+3L,5L,6],wave[-15,-.9d+3L,6.8L,8],wave[-15,-.9d+5L,8.5L,10]}

waves2[L_,d_]:={wave[d+1.5 L/(Sqrt[2]),25,-3L,7],wave[d+1.5L/(Sqrt[2]),25,-L,8],wave[d+1.5 L/(Sqrt[2]),25,L,10],wave[d+1.5 L/(Sqrt[2]),25,3L,6],wave[d+1.5 L/(Sqrt[2]),25,5L,9],wave[d+5 L/(Sqrt[2]),25,6.8L,7],wave[d+8.5 L/(Sqrt[2]),25,8.6L,5]}

waves3[L_,d_]:={wave[-.7d,1.2d,-3L,3],wave[-.7d,1.2d,-L,2],wave[-.7d,1.2d,L,4],wave[-.7d,1.2d,3L,3],wave[-.7d,1.2d,5L,4],wave[-d+5L/(Sqrt[2]),1.2d+5L/(Sqrt[2]),6.8L,3],wave[-d+8L/(Sqrt[2]),1.2d+8L/(Sqrt[2]),8.6L,2]}

force[L_,d_]:=Graphics[Text[Style[Row[{"force = ",NumberForm[130 (L^2)/(d^4),4]," dynes"}],24,Bold],{5,-11}]]

Manipulate[
Show[waves1[L,d],plate1[L,d],waves3[L,d],plate2[L,d],waves2[L,d],force[L,d],PlotRange->{{-15,25},{-12,20}},AspectRatio->1,ImageSize->{600,400}],{{L,1.5,"L (m)"},1,2,Appearance->"Labeled"},
{{d,1,"d (μm)"},.5,5,Appearance->"Labeled"},ControlPlacement->Top,
TrackedSymbols:>{L,d},
SaveDefinitions->True]