Here is an example of Four(4) active LEGO Mindstorms attachments built-in the frame. Two by two they work asynchronously since all of them are connected to the two separate middle motors of the SUV robot via the frame.
The left attachments work synchronously, and the right attachments are also synchronized couple.
These specific attachments are meant to do nothing in particular, but to serve as an example. Their purpose is to demonstrate different ways in which one could add an attachments to the frame. Experiment. Think and invent better frame with real world attachments that could actually do efficient work and accomplish a mission. Take a video then and share it with us.