Pencil is a free and opensource tool for making diagrams and GUI prototyping that everyone can use. Top features: * Built-in stencils for diagraming and prototyping * Multi-page document with background page * Inter-page linkings! * On-screen text editing with rich-text supports * Exporting to HTML, PNG, Openoffice.org document, Word document and PDF. * Undo/redo supports * Installing user-defined
![Pencil – Get this Extension for 🦊 Firefox (ja)](https://cdn-ak-scissors.b.st-hatena.com/image/square/2c533f0676b6df1b799020e1edd38075fd67b055/height=288;version=1;width=512/https%3A%2F%2Faddons.cdn.mozilla.net%2Fuser-media%2Fpreviews%2Ffull%2F24%2F24711.png%3Fmodified%3D1530208382)