Although it might seem strange to emulate an Apple on an
Apple, it isn't. Everybody does it when using Classic under
OS X. VMac and Basilisk can be used to emulate older Macs
(System 6). To emulate an Apple IIe one can use OSXII.
Finally, it is possible to emulate the first Apple, the
Apple I, with Cocoa Pom.
Apple OS7.5 is freely available from here
Cocoa Pom
OSXII
Vmac
Basilisk