>>10033318I think...
The 1x1 round plate
It's like the ATOM of lego universe, the smallest, still recognizable thing that is still unmistakably "LEGO", it's the brick that has the highest size/usage ratio.
And really, you can place it into whatever context you want and people will quickly get it what it is.
>Gold, Silver colored ones? They are coins!
>Trans colored ones in a chest?They are gems!
>Trans-Green in bowl?It's candy!
>Trans-Red at the end of the gun?Laser blast!
>Trans-Blue at the back of a spaceship / jet?afterburn glow!
>Bunch of black dots at a pic-nic? ANTS!