After looking at the wallpaper, I noticed the following.
1. Some of the socket pieces around the border appear to have "CRAFTSMAN" engraved in them. (See attachment for a close-up of this)
2. The other socket pieces have text engraved in them, but I can't read it.
3. All of the tools in the picture can be used to drive nuts or bolts(wrenches, adjustable wrench, pliers, sockets)
4. Some of the above sockets have a unique star-shaped head
5. The large paintbrush has a different texture on it
6. The guy with the black top hat is holding something interesting...
7. The minibot with tank treads appears to have a V-block engine on it
8. The robot on the large board(behind the girl pointing at the ceiling and holding the gear thing in her other hand) has interesting motor placement
9. There's something interesting about the drum(for lack of a better word) that can be seen in the background. It has something different on one of its vents(it can be seen next to the guy holding what looks like part of a car transmission).
All of those are circled in the image below.
Here's a link to the image.
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"You know, it's amazing how many things you can take apart with just one ordinary screwdriver!" - Calvin, from Calvin and Hobbes
"There's nothing a little duct tape and surgical tubing can't accomplish." - Sheldon J. Plankton