Before starting on the composition with the much-used 子 zǐ, let’s go back to its origin. We had seen that 巳 had for origin a writing which represented a foetus, see here.
The ancient spelling of 子 shows a close idea, a head with a body and arms:
子 zǐ means child, youth. No wonder!
When 子 is placed on the left, its line is no longer horizontal, but starts a little lower and goes upwards as in 孔, kǒng.
孔, kǒng, hole, opening.
In the old spelling, we can see the child on the left in front of its mother’s breast to drink her milk. The idea of a hole comes from the mouth, opening, of the child ready to drink; some people think that it is rather the hole in the breast from which the mother’s milk flows.