Copiests in the area would insert their own version of the pictures. The script would change over the years from that of the original artist, to that of the copiests. When similar art forms are discovered, it is not easy to think of diffussion. After all, we would never take a small boat across the oceans, but, even today, there are people who do. Single navigators with a dream, or even families with a sturdy, albiet small boat.
Modern boats are better equipped than the open boats used centuries ago.
A journey can be made, but because of language differences, quickly forgotten.