environmental citybuilder prototype

Cat Flynn 944ca8c3f2 extract struct to file		2022-12-07 00:13:11 +00:00
half-earth	extract struct to file	2022-12-07 00:13:11 +00:00
.gitignore	add gitignore	2022-12-03 16:26:13 +00:00
gdd.md	add gdd	2022-12-03 16:01:14 +00:00