I really like the simplicity of this piece but, for me, those needed to either have a transparent background or be on a table or picnic cloth. That grey background doesn't seem to match the vibe of the rest.

 Vou usar como avatar dont

I liked the look of the coffee

 thanks all :D

- Neat! -

 Nice pie, but I saw the pi right away

 Nice, took me a while to find it :)

 it is so obvious!  but ok, i though the challenge was about hiding it hard 

Of course, if you connect the symbol to other pixels of the same color it becomes even harder. You could also draw a flat area and say that it contains the symbol :p