Why do some tiles have red “chips” on them in Civilization 5?
After playing many games of Civ 5, I have noticed the occurrence of strange red marks which appear on tiles occasionally. Upon closer inspection it seems to have a devil or bug-like aspect. I have conjectured that it could be:
1) Blood that has been shed in a skirmish
2) A developer's eccentric idea of an Easter Egg
3) A graphics card, driver or graphics rendering issue
4) A dark ritual performed my some primeval cult
Is there any significance to this feature or can we only speculate?