Burping may not be the picture of politeness in American society, but in some cultures a hearty belch shows appreciation for a good meal.

Undoubtedly, the drawer of the picture aims at reminding us that we should use technology in a proper way and not be too tech-dependent to solve the simple problem independently.

Here is a better picture. I claim that what will be going through C is this shaded parallelogram to the left of C.