\documentclass[tikz,margin=5pt,tightpage]{standalone}
\usepackage{varwidth}
\usepackage{tikz}
\usepackage{verbatim}
\usetikzlibrary{positioning}
\usepackage[utf8]{inputenc}
\usepackage{fullpage}
\usepackage{fourier}
\usetikzlibrary{calc,3d}
\begin{document}
\begin{tikzpicture}[x = {(-0.5cm,-0.5cm)},
y = {(0.9659cm,-0.25882cm)},
z = {(0cm,1cm)},
color = {black},scale=1]
\draw[draw=black,opacity=.8,very thick,line join=round]
(0,0,0.3) --
(0,0,-0.3) --
(0,10,-0.3) --
(0,10,0.3) --cycle ;
\draw[draw=black,opacity=.8,very thick,line join=round]
(10,2,0.3) --
(10,2,-0.3) --
(0,0,-0.3) --
(0,0,0.3) --cycle ;
\begin{scope}[canvas is xy plane at z=-0.3]
\coordinate (A) at (0,0);
\coordinate (B) at (10,2);
\coordinate (C) at (8,8);
\coordinate (D) at (0,10);
\coordinate (E) at (0,0);
\coordinate (F) at (0,10);
\coordinate (G) at (10,10);
\coordinate (H) at (10,0);
\fill[green!20,fill opacity=0.9] (A) -- (B)--(C)--(D)--cycle;
\draw[black,very thick] (A) -- (B)--(C)--(D)--cycle;
\end{scope}
%****************************
\begin{scope}[canvas is xy plane at z=0.3]
\coordinate (A) at (0,0);
\coordinate (B) at (10,2);
\coordinate (C) at (8,8);
\coordinate (D) at (0,10);
\coordinate (E) at (0,0);
\coordinate (F) at (0,10);
\coordinate (G) at (0,5.6);
\coordinate (H) at (3.95,11);
\fill[green!20,fill opacity=0.97] (A) -- (B)--(C)--(D)--cycle;
\draw[black,very thick] (A) -- (B)--(C)--(D)--cycle;
\end{scope}
%***************************************************************
\draw[draw=black,opacity=.8,very thick,line join=round]
(10,2,0.3) --
(10,2,-0.3) --
(8,8,-0.3) --
(8,8,0.3) --cycle ;
\draw[draw=black,opacity=.8,very thick,line join=round]
(0,10,0.3) --
(0,10,-0.3) --
(8,8,-0.3) --
(8,8,0.3) --cycle ;
\end{tikzpicture}
\end{document}
