For those who don't know Burgopak, got to their website Burgopak.com to find out more. The special thing about Burgopak is that they invented a way that you pull out a card on one side and from the other side something else slides out. However I managed to figure out how it works without even looking at one in real life, but there is still something that is called a patent. Burgopak patented this design so they may only produce this and other companies only may produce it when they buy it out of them. However I can still use this for my school projects because I am not selling it and will use it for the next project. Maybe I will make an tutorial about how it works, however it ain't easy to mass produce it manually. It can only can be mass produces if you build a special machine for it.
Credits to: Burgopak.com for this amazing concept.