%
% tikztemplate.tex -- template for standalon tikz images
%
% (c) 2021 Prof Dr Andreas Müller, OST Ostschweizer Fachhochschule
%
\documentclass[tikz]{standalone}
\usepackage{amsmath}
\usepackage{times}
\usepackage{txfonts}
\usepackage{pgfplots}
\usepackage{csvsimple}
\usetikzlibrary{arrows,intersections,math}
\begin{document}
\def\skala{1}
\begin{tikzpicture}[>=latex,thick,scale=\skala]

\definecolor{rot}{rgb}{0.8,0,0}
\definecolor{blau}{rgb}{0,0,1}
\definecolor{gruen}{rgb}{0,0.6,0}

\draw (-1,-1) rectangle (1,1);
\node at (-1,-1) [below left] {$0$};
\node at (1,-1) [below right] {$K$};
\node at (1,1) [above right] {$K+iK'$};
\node at (-1,1) [above left] {$iK'$};
\node at (0,0) {$u$};

\begin{scope}[xshift=4cm]
\fill[color=rot!20] (-1,-1) rectangle (1,1);
\node at (-1,-1) {$0$};
\node at (1,-1) {$1$};
\node at (1,1) {$\frac1k$};
\node at (-1,1) {$\infty$};
\node[color=rot] at (0,0) {$\operatorname{sn}(u,k)$};
\end{scope}

\begin{scope}[xshift=7cm]
\fill[color=blau!20] (-1,-1) rectangle (1,1);
\node at (-1,-1) {$1$};
\node at (1,-1) {$0$};
\node at (1,1) {$\frac{ik'}k$};
\node at (-1,1) {$\infty$};
\node[color=blau] at (0,0) {$\operatorname{cn}(u,k)$};
\end{scope}

\begin{scope}[xshift=10cm]
\fill[color=gruen!20] (-1,-1) rectangle (1,1);
\node at (-1,-1) {$1$};
\node at (1,-1) {$k'$};
\node at (1,1) {$0$};
\node at (-1,1) {$\infty$};
\node[color=gruen] at (0,0) {$\operatorname{dn}(u,k)$};
\end{scope}

\end{tikzpicture}
\end{document}