What is your favourite design?

Now, this is pretty simple and obvious for me.

My favourite design has to be The Camera, simply because the idea of capturing a moment, a scene, an emotion on camera, and being able to remember it forever and keep it safe unlike the brain, is just brill. With a camera, the model and photographers personality, style, flare, and emotions can be conveyed upon a single shot, this I think just sums up the brilliance of this simple yet complex design. 

Thanks to Abu Ali Al-Hasan Ibn al-Haitham who started the camera series off!

What's your favourite design? It can be anything! Nature or Technology!