If you are a student or someone that is after trying to make something into a product and its from plastic then I would recommend signing up for the tips from ProtoMold, go here. Well not only do they do the online tips but they also make little parts that explain what the tip is talking about. So in the one above it describes the parts of a plastic mould tool, core side, sliders, sprue etc. So if you are unsure and are getting a little baffled by the naming convention this is a really helpful little desktop gadget.
This box above is the gadget they made for describing hinges made within the part, a clever trick to reduce the part count of a part. After all why make make the box from 6 parts when you can make it from one, no tolerance problems, no assembly fixtures and only one mould tool.
This was one of the more interesting piece is the Reptangles. Its a patented design that is in the same realm as Lego but more designed. The part looks like a turtle, their words, and has 56 connectors per part but they are inexpensive as they are straight pull connectors within the mould. Protomold made the parts in prototype tooling but from the production material to get a far better feel for the finished product.
So head over to to ProtoMold and sign up for there design tips, you never know what you might learn.