Seals have a long tradition in China and are mainly a general term for printing stamps. The seals below are engraved in stones and were used, as can be seen easily, with red ink paste. The two types of engraving, yin and yang, are illustrated.
Note:
the dimensions of the carved stones vary. In order to appreciate the composition and the skill of the artist, the pictures have been enlarged somewhat.

Four Horizons
Travelling the four horizons

Discreet Retreat
If useful, I put myself into it;
if not, I discreetly retreat.

Sage
The sage is not encumbered by his own self

Wanderer

Learning
A tireless spirit keeps learning

Success Not Pride
Working to succeed but not boasting it

Emptiness
Relying on emptiness brings blindness

Settle Oneself
In settling oneself, care of the same for others

Collection of Carved Stones
by Ngan Siu-Mui