I use the following code to fill a specific area with dots. Can the dots positions be randomized, and can the dots size be altered.
\documentclass{beamer}
\beamertemplatenavigationsymbolsempty
\usepackage{tikz}
\usepackage{pgfplots}
\usepackage{tkz-fct}
\begin{document}
\begin{frame}[fragile,t]
\frametitle{}
\begin{tikzpicture}[scale=.9, transform shape]
\fill[pattern=dots,pattern color = blue] (1.,.46) -- ++ (4.,1.66) -- ++ (-.6,.8) -- ++ (-3.68,-1.84) -- cycle;
\end{tikzpicture}
\end{frame}
\end{document}

Relatedlinks on them can help you – Ignasi Jul 10 '18 at 06:40