For my object deconstruction I took apart a toy that is meant to be shot via slingshot up and propeller down. It has an LED light in it, and given the general, very cheap build quality of these toys I was very curious as to how this simple circuit was constructed.
This is an image of the toy, with an LED light close to the end of the main thick head, near where the propeller is to be when it is folded. The button that turns this light on and off is on the opposite side, and its all molded together to make the housing reliably sturdy.
This molded nature was a very big pain for me to deal with, because the plastic did not come apart without some significant effort, force, ripping and cutting. I assumed you could pry it apart at the seams, but these seams were either melted or glued together so that it acted almost as one contiguous piece. After pulling away the head part that was designed to make a whistling sound as the toy was rocketed, I was forced to essentially destroy the rest of the housing to get to the actual electronic bits that made the light function as it did.
Once I was able to rip the components out of the housing I got to look at what they were. In the packaging lied one LED and one button connected via some solder on one of the button prongs. There were also 3 coin battery cells that were simply held between the LED and the button using the form of the case to keep them in place. The batteries connected the button and the LED so that they basically acted as the wire and the power source at the same time. This is a rather cheap way of making this circuit, but if it works and saves the manufacturer pennies, then it is efficient enough for them.
Below is the very basic circuit diagram I was able to create out of the design of this toy.