PatchFusion is a third-party program that allows the user to easily combine the contents of two patch files.The user starts by selecting two patch files - a destination (top row), and a source (bottom row). The file serving as the destination is the one that will be edited. Patch Fusion displays each individual shape for both files, allowing the user to easily delete, insert, or replace the shapes in the destination file with the shapes in the source file.
PatchFusion can also be used to edit Kitterspeak, shape properties (furre position, shape position, etc), and export shapes to bitmap images or animated GIFs.
Mercenary Enclave page for Patch Fusion, with full feature list, version history, and download links.