\usetikzlibrary{calc,trees,positioning,arrows,chains,shapes.geometric,%
decorations.pathreplacing,decorations.pathmorphing,shapes,%
matrix,shapes.symbols,plotmarks,decorations.markings,shadows,backgrounds}


\pgfdeclarelayer{background}
\pgfdeclarelayer{foreground}
\pgfdeclarelayer{L0}
\pgfdeclarelayer{L1}
\pgfdeclarelayer{L2}
\pgfdeclarelayer{L3}
\pgfsetlayers{background,L0,L1,L2,L3,main,foreground}

\newcommand{\scale}{0.4}

\begin{tikzpicture}[scale=\scale,every node/.style={scale=\scale},on grid ]

  \definecolor{LCUFill}{rgb}{0,0.5,1}
  \definecolor{DrawColor}{rgb}{0,0,0.5}
  \definecolor{LCUFill}{rgb}{1,1,1}
  \definecolor{DrawColor}{rgb}{0,0,0}

  \tikzstyle{TextStyle}=[scale=1.8, text centered]

  \tikzstyle{CTU}=[draw=DrawColor, fill=LCUFill, very thick]
  \tikzstyle{CU}=[draw=DrawColor, thin]
  \tikzstyle{PU}=[draw=DrawColor, thin, densely dashed]

  \node[TextStyle] at (8,16.5) {$64\times64$ - CTU};
  \draw[CTU] (0,0) rectangle ++(16,16);  	% 64x64

  %% 32x32
  \draw[CU]  (0,0) rectangle ++(8,8);			% 32x32
  \draw[CU]  (8,8) rectangle ++(8,8);			% 32x32

  %% Q1
  \draw[CU]  (0,8) rectangle ++(4,4);			% 16x16
  \draw[CU]  (4,12) rectangle ++(4,4);	  % 16x16
  \draw[CU]  (4,12) rectangle ++(2,2);			% 8x8
  \draw[CU]  (6,14) rectangle ++(2,2);			% 8x8

  %% Q3
  \draw[CU]  (0,0) rectangle ++(4,4);			% 16x16
  \draw[CU]  (4,4) rectangle ++(4,4);			% 16x16
  \draw[CU]  (4,4) rectangle ++(2,2);			% 8x8
  \draw[CU]  (6,6) rectangle ++(2,2);			% 8x8

  \draw[PU]  (4,4) rectangle ++(1,1);			% 4x4
  \draw[PU]  (5,5) rectangle ++(1,1);			% 4x4

  \node[TextStyle] at (12,12) {$32\times32$};
  \node[TextStyle] at (2,14) {$16\times16$};
  \node[TextStyle] at (5,13) {$8\times8$};

  \node[TextStyle] (CULabel) at (9.5,6) {CU};
  \draw[black, -latex] (CULabel) to (7,7);

  \node[TextStyle] (PULabel) at (2.5,5.5) {PU};
  \draw[black, -latex] (PULabel) to (4.5,4.5);


% 	%H.264
% 	\node[TextStyle] (PULabel) at (10.5,4.5) {\textcolor{red}{MB}};
% 	\draw[black, -latex] (PULabel) to (13,3);
% 	\draw[CU, draw=red]  (12,0) rectangle ++(4,4);			% 16x16
% 	\draw[CU, draw=red]  (14,0) rectangle ++(2,2);								% 8x8
% 	\draw[CU, draw=red]  (12,2) rectangle ++(2,2);								% 8x8
% 	\draw[CU, draw=red]  (15,0) rectangle ++(1,1);								% 4x4
% 	\draw[CU, draw=red]  (14,1) rectangle ++(1,1);								% 4x4

\end{tikzpicture}