Windows 3.0 undated 1989 build

3.00.13 is a pre-release version of the Calculator application, made by Craig Brockschmidt, in an unknown Windows 3.0 beta build. He posted a screenshot of a Windows 3.0 beta on his website, running this version of his calculator application.

Given that the calculator in Windows 3.00.55 has the version number 3.00.16, the build of Windows 3.0 shown in the screenshot probably isn't 3.00.13, though it's certainly earlier than 3.00.55.