The box has to be functional as it needs to be opened to get to the next box, so I started thinking about how I would want to open my box.

I like the ideas of sliding the lid off the box, it is simple and it also means you gradually see what is inside.

I like the idea that the lid could have a handle and be lifted off, it is like you are being presented with what is inside.

I like this idea more, as it is the next step of the example above. By taking the lid off you are still being presented by what is inside because the sides fall open, presenting the box inside.