共

共 is actually the original form of 供 (공).

It was originally created to depict two hands holding up an object. Meaning is “to offer” or “to present (something)”.

Over time, this meaning was largely shifted to 供 (formed by adding the 亻 “person” radical).

共 then took on the meaning “together,” “shared,” or “in common.”

In oracle bone script (甲骨文 jiǎgǔwén):

The lower part 廾 (받들 공) represents hands holding or offering something.

On top of the hands, a square shape (representing an object) was drawn.

In bronze inscriptions (金文 jinwen):

That square evolved into something resembling 廿 (스물 입).

By the regular script (楷書 kǎishū):

Even 廾 changed shape, giving us the form 共 we see today.

In ancient times, 共 and 供 were interchangeable, used for both “to offer” and “together.”