Geohashes no relation regular grid
Geohashes with 2, 4, 6, ... e digits (even digits) are represented by Z-order curve in a "regular grid" where decoded pair (latitude, longitude) has uniform uncertainty, valid as Geo URI.
Geohashes with 1, 3, 5, ... d digits (odd digits) are represented by  "И-order curve". Latitude and longitude of the decoded pair has different uncertainty (longitude is truncated).
no relation