Straightforward and easy to tweak invoice template.
Updates may be available at https://github.com/eroux/latex-yait
The file is under the CC0 license (https://creativecommons.org/publicdomain/zero/1.0/).
The abntex2 class and the abntex2cite package are intended to assist the preparation of technical and scientific documents, such as theses, articles, research projects and other
academic papers, based on Associação Brasileira de Normas Técnicas (ABNT) rules used in Brazil.
LaTeX is great for plotting mathematical shapes -- here we present an example of a cardioid.
A cardioid is a plane curve created by tracing a point on the perimeter of a circle rolling around a fixed circle of the same radius. Read more
Original source: http://www.altermundus.fr/pages/euclide.html