Home - Pencil ProjectAn open-source GUI prototyping tool that's available for ALL platforms. Pencil is built for the purpose of providing a free and open-source GUI prototyping tool that people can easily install and use to create mockups in popular desktop platforms. The latest stable version of Pencil is 3.1.1 which contains stability fixes and many new features. More details can be found in the release notes. Proje
