public List<GeoHash> getAdjacent() {
GeoHash northern = getNorthernNeighbour();
GeoHash eastern = getEasternNeighbour();
GeoHash southern = getSouthernNeighbour();
GeoHash western = getWesternNeighbour();
return Arrays.asList(
northern,
northern.getEasternNeighbour(),
eastern,
southern.getEasternNeighbour(),
southern,
southern.getWesternNeighbour(),
western,
northern.getWesternNeighbour(),
this);
}
