Mac OS X 10.6 Snow Leopard , Mac OS X 10.7 Lion , Mac OS X 10.8 Mountain Lion , Mac OS X 10.9 Mavericks , Mac OS X 10.10 YosemiteWindows XP , Windows Vista , Windows 7 (Seven) , Windows 8 , Windows 8.1
This program is called "Pencil2D" (Former name : "Pencil Animation"). It is an animation/drawing software for Mac OS X, Windows, and Linux. It lets you create traditional hand-drawn animation (cartoon) using both bitmap and vector graphics. Pencil is free and open source.