Here’s an example illustration made with Jpgfdraw following a drawing in Singer/Thorpe Lecture Notes in Elementary Topology and Geometry, I made freehand it to illustrate homotopy of paths in my notes.

Screenshot:

Output in pdf format: homotopy.pdf
Jpgfdraw binary file: homotopy.jdr
exported tex file: homotopy.tex

LaTeX main document:

\documentclass[a4paper,10pt]{article}
\usepackage[landscape]{geometry}
\usepackage{amsmath,pgf}
\pagestyle{empty}
\begin{document}
\centering
\input{homotopy}
\end{document}