Executor is ARDI's (http://www.ardi.com) environment for running Macintosh applications. (A Blue Box in Apple marketing speak). It is available for demo or purchase for Linux, DOS, OpenStep, and Win32, all on Intel. Executor allows you to run many System 6 and 7 applications on your PC by emulating the Mac toolbox and recompiling code to native on the fly.
(The link is from a screenshot of a Linux/X setup running Executor to use Adobe Photoshop and MS Word)