Tikz is a language for creating vector graphics. It can be used in LaTeX by including the package tikz
\usepackage{tikz}
Tikz is a german recursive acronym "TikZ ist kein Zeichenprogramm" ("TikZ is not a drawing program"). The following file is a minimal example of tikz.
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw (0,0) --(0,10);
\end{tikzpicture}
\end{document}
It will give output as
When coordinates are changed the output coordinates are adjusted
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw (0,0) --(8,10);
\end{tikzpicture}
\end{document}
Custom shapes are also possible like
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\draw [fill = violet,text = white] (-2,0) rectangle (1,1) node[pos=.5] {{\tiny Text 1}};
\draw [fill = violet,text = white] (3,0) rectangle (5.5,1) node[pos=.5] {{\tiny Text 2}};
\draw [->,line width=0.4mm] (1,.5) -- (3,0.5);
\end{tikzpicture}
\end{document}
This will give output as
Being a programming language, it has got facilities for looping. Below given program draws line with angle increasing
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\foreach \i in {0,5,...,360}
{
\draw (0,0) --(\i:3cm);
}
\end{tikzpicture}
\end{document}
Removing steps we get
\documentclass{article}
\usepackage{tikz}
\begin{document}
\begin{tikzpicture}
\foreach \i in {0,...,360}
{
\draw (0,0) --(\i:3cm);
}
\end{tikzpicture}
\end{document}