Grassland: These open lands have especially thick topsoils making them excellent food producing areas. Food production can be increased by rrigation. Roughly half of the Grasslands also have some resources, making them excellent city sites. Grasslands may be converted into Forests for increased resource production.¹
There seems to be two types of grassland. The regular on the left and the enhanced on the right. I have looked in the manual and the games CIVILOPEDIA finding no reference to the later. Yet it is the preferred, build a city and it is nice to have a few of these, more production, more trade. What is that little shape?
The curious thing about them for me is that unlike other terrain types they only form in certain areas on the map. Any grassland that happens to be in that area is displayed as the enhanced version. Namely in stripes that occur in bands two squares wide running at 45 degree angles across the map. There location seems fixed.
1) From the CIV dos manual: CIVILIZATION Build An Empire To Stand The Test Of time - page 26

There seems to be two types of grassland. The regular on the left and the enhanced on the right. I have looked in the manual and the games CIVILOPEDIA finding no reference to the later. Yet it is the preferred, build a city and it is nice to have a few of these, more production, more trade. What is that little shape?
The curious thing about them for me is that unlike other terrain types they only form in certain areas on the map. Any grassland that happens to be in that area is displayed as the enhanced version. Namely in stripes that occur in bands two squares wide running at 45 degree angles across the map. There location seems fixed.

1) From the CIV dos manual: CIVILIZATION Build An Empire To Stand The Test Of time - page 26