SK8 (pronounced "skate") was a multimedia authoring environment developed in Apple's Advanced Technology Group from 1988 until 1997.

Although around 1993 a team was assigned by the Apple Product Division to release a SK8 runtime, the limitation of the Mac's capabilities as well as the shift to the PowerPC chip made such a large project intractable.

Through preferences settings, MacFrames was used to emulate a large variety of object systems, including IntelliCorp's KEE.

This research, in concert with users developing actual applications and prototypes at Apple, yielded the object model used in SK8.

Kleiman created an IPC init for the Mac to allow MacFrames to communicate with other processes, in particular, HyperCard.

Instead of using an RPC API, one simply set the object's property with the desired value and callback for the results.

The first version of the SK8 graphics system was designed to extend HyperCard, allowing cards to have multiple layers rather than a single "background" template.

In 1989 Kleiman joined David Canfield Smith and Larry Tesler to design and implement the first version of AppleScript.

The SK8Script debugger was re-implemented at the assembler language level (previously in Lisp) and the compiler and runtime performance improved.

Hence, properties were not simply names that acted as keys to set or retrieve values, but in addition possessed arbitrary behavior.

Actors became visible when they were placed upon the Stage, an invisible background object that captured user events to provide interactivity.

An object known as the "halo" provided resize handles and other widgets for manipulation in a visual development environment.

For instance, the BevelRenderer could be used to bevel the edges around an Actor, producing an effect like Windows 3.x controls or the title bar in NeXTSTEP.

A key element of the Builder system was the "Overviewer" panel, which held a categorized list of all of the objects in the currently opened project.

[12] These could be examined and edited by double-clicking on them, or by clicking in an associated pop-up menu that appeared on the object when it was selected in the GUI builder.

SK8 did, however, include a system for editing and programming complete menu bars, a feature that HyperCard lacked.

Another oft-requested feature from HyperCard was a media editor, which allowed Macintosh resources to be moved in and out of the project.

Under SK8, SK8Script could interact directly with the encapsulated code, setting variables, calling functions and returning results.