The solitaire game variant FreeCell was the test application for Win32s, the 32 bit extensions and API to the 16 bit Windows 3.1. By default FreeCell was installed as a 32 bit application, so the user could verify that the 32 bit extensions were functioning correctly.
Figure 33. FreeCell Solitaire Game Variant
FreeCell has also been included in Windows 95 and Windows NT 4.0. However, the version supplied with Windows 95 is a 16 bit version.
There is a rumor that every on of its 65,536 different starting positions can be won.
For more information see:
Playing FreeCell without a Mouse