How to use for (or foreach) instead of hardcoding

I am new to Tikz and I am trying to draw the followingImage may be NSFW.
Clik here to view.

So far I did this manually but I was wondering how a foreach-Loop would work.

\begin{document}    \begin{tikzpicture}[    %   \def\compOneOne{5}    %   \def\nodeName{C1}        node distance = 0pt,        square/.style = {draw=blue!60, fill=blue!5, very thick,             minimum height=3em, minimum width=3em, % <---            outer sep=0pt},        square2/.style = {draw=purple!60, fill=blue!5, very thick,                 minimum height=3em, minimum width=3em, % <---                outer sep=0pt},        ]        %Nodes        \node[square]   (a1) {};        \node[square, right=of a1] (a2) {};        \node[square, right=of a2] (a3) {};        \node[square, right=of a3] (a4) {};        \node[square, below=of a1] (b1) {};        \node[square, right=of b1] (b2) {};        \node[square, right=of b2] (b3) {};        \node[square2, below=of b1] (c1) {};        \node[square2, right=of c1] (c2) {};        \node[square2, right=of c2] (c3) {};        \node[square2, right=of c3] (c4) {};        \node[square2, below=of c1] (A1) {};        \node[square2, right=of A1] (A2) {};        \node[square2, right=of A2] (A3) {};        \node[square2, right=of A3] (A4) {};        \node[square2, right=of A4] (A5) {};        \node[square2, right=of A5] (A6) {};        \node[square2, right=of A6] (A7) {};        \node[square2, right=of A7] (A8) {};        \node[square2, below=of A1] (B1) {};        \node[square2, right=of B1] (B2) {};%       \node[square2, below=of B1] (C1) {};%       \foreach \number in {1,...,\compOneOne}{%           \node[square2, right=of \nodeName] (N-\nodeName) {};%           \nodeName = N-\nodeName;%           %       }    \end{tikzpicture}\end{document}

The stuff that's commented out shows my own attempts on it.Furthermore I was struggeling with naming conventions and how to rename my variable efficiently.It would be very nice of you to help me. Thanks in advance!