Creating random patterns in TikZ

Question

I'm interested in doing two (not completely) separate things in TikZ, if I should open another question for one part, please tell me so.

What I'm interested in is:

1. Create a random array of filled shapes.
2. Create a random shape.

and maybe combine the two, but that will be the next step. what I want is to define the shape limit (like 10pt, 20pt etc.) and not to determine it's path.

EDIT:

Here's what I got so far (can't answer my own question yet) , for instance:

\begin{tikzpicture}
\def\x{rnd*4}
\foreach \i in {4,8,...,16} {
\edef\x{\x*rnd+\i}          
\draw [fill=black,
        decoration={random steps,segment length=.5cm,amplitude=.5cm},
        decorate,
        rounded corners=.3cm]
     (\x,\x) -- (\x+3,\x) -- (\x+3,\x+3) -- (\x,\x+3) -- (\x,\x);
   }
\end{tikzpicture}

will result in

As you can see it's not really random but "ascending".

So, to narrow it down :

I would like the patterns to sit on random (or seemingly random) places, without intersecting each other.

Thanks in advance.

Answer 1

Since no constraints on smoothness of the result, I use pentagon for illustrations where I defined a macro (called \irregularshape) to draw a pentagon, whose vertices are determined randomly.

 \documentclass[]{standalone}
 \usepackage{tikz}

 \begin{document}
 \newcommand\irregularshape[2]{
 \begin{tikzpicture}
 \tikzstyle{every node}=[coordinate]
 \foreach \t/\x/\y in {1/18/1, 2/90/1.2, 3/162/1.4, 4/234/1.2, 5/306/1}
 {\pgfmathsetmacro\lenx{rnd*#1}   % seed
 \pgfmathsetmacro\leny{rnd*#2}    % seed
 \node(\t) at (\x+\lenx:\y+\leny) {};}                 
 \foreach \from/\to in {1/2, 2/3, 3/4, 4/5, 5/1}     
 {\draw [fill=black,rounded corners=1mm] (\from) -- (\to);}              
 \end{tikzpicture}
 }

 %Parameters (#1,#2) are changeable, yielding vertices

 \begin{tabular}{cc}
 \irregularshape{0.8}{1}&\irregularshape{1}{.2}\\
 \irregularshape{1.4}{.3}&\irregularshape{.3}{2} \\
 \irregularshape{.3}{.4}&\irregularshape{2}{.3} \\
 \end{tabular}
 \end{document}

and an image is included.