[baq]

OS/2 gets pretty close with a [ / ]

http://en.wikipedia.org/wiki/OS/2#mediaviewer/File:Os2W4.png

[wolfgke]

This is a screenshot from OS/2 Warp 4, which was released after Windows 95 (source: http://www.os2museum.com/wp/?page_id=132). OS/2 Warp 3 that came before Windows 95 had the following set of Window buttons:

http://www.guidebookgallery.org/screenshots/os2warp3

[killercup]

Looks like `[x]/2 == [/]`.