This page introduce a pretty cool LaTeX package: TikZ.
TikZ— It can be used to draw graphics directly with TeX commands in Latex.
TikZ and PGF are TeX packages for creating graphics programmatically. TikZ is build on top of PGF and allows you to create sophisticated graphics in a rather intuitive and easy manner.
It comes with very good documentation and an extensive collection of examples: http://www.texample.net/tikz/ (Show all examples | Show in chronological order)
(PGF and TikZ examples gallery — browse by: Features | Tags | Technical areas | Non-technical areas |Authors)
See below for some examples from texample.net :
- Example: Annotated 3D box (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Random city (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Filesystem tree (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Flowchart (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Gajski-Kuhn Y-chart (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Hierarchical diagram (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Highlighting elements in matrices (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Knowledge Base Exchange framework (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Neural network (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Network Topology (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Focused ion beam system (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Fireworks (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Fitting text to a shape (Download as: [PDF] [TEX] • [Open in Overleaf])

- Example: Poppy flower (Download as: [PDF] [TEX] • [Open in Overleaf])
