Phun 2D Physics Sandbox is free for non-commercial use (see license). Phun combines physics and art in a playful way with open ended undirected gameplay. Phun is not just a game - it is much more! Phun is educational, entertaining and pretty addictive! To learn Phun easily and quickly, read this getting started tutorial. If you have problems, please read the FAQ or ask for help in the forums. There are lots of great examples in the media section, including the original Phun video, which is very instructive. There are also and lots of scenes you can download for free from Phunbox.
You'll need a decent computer with hardware 3D (well, 2D) acceleration. Remember, Phun is still beta, so it still has a few glitches.
To learn what is new in the latest version of Phun, see the changelog. We hope you enjoy Phun and spread the word to your friends!
Phun 是什么？Phun是Umeå大学的学生Emil Ernerfeld为自己的计算机作业而开发的一个基于物理规律的工具软件.使用者可以随意而且轻易的创建物体，并给它们之间创建弹簧、链条等联系，重力、摩擦力、弹力、加速度等等，一切都符合物理规律.这个软件的开发目的是为了让物理教学、研究更直观有效。
Windows Phun beta 4.22 installer (2.62 MB) – recommended for Windows XP and earlier
Phun beta 4.22 zip archive (3.65 MB) – recommended for Windows Vista – extract to a directory with write access (such as My Documents or the desktop)
Linux Phun beta 4.22 for 32-bit Linux, tar.bz2 archive (3.05 MB)
Phun beta 4.22 for 64-bit Linux, tar.bz2 archive (2.99 MB)
MacOS Installation: Double click the downloaded file to mount it. Open the mounted disk image (found on your desktop) and copy the Phun folder to your Applications directory.
Phun beta 4.22 (7.42 MB) – for Mac OS X 10.4 and later, works on both x8