The high crosses of Ireland served the same function as stained glass windows in churches in later ages - they were teaching tools. The carvings in the crosses depicted scenes from the Bible. People who could not read could learn the stories through pictures.
The photo here is a detail from the east side of the Muiredach high cross at Monasterboice near Dublin and is a two-fer: Adam and Eve on the left, and the death of Abel on the right. A natural to put them together - naked Adam and Eve eat the apple and immediately clothed Cain kills Abel in the field.