found the masses

main.py

@@ -23,6 +23,8 @@ grass_high = 0.6
 mountains = 1
 block = "█"
 block = block + block
+LAND = "land"
+WATER = "water"
 
 def generate_world(seed):
     try:
@@ -46,8 +48,8 @@ def generate_world(seed):
     except Exception as e:
         print(e)
 
-def terrain_matches(cell1, cell2):
-    return cell1["is_land"] == cell2["is_land"] or cell1["is_water"] == cell2["is_water"]
+def terrain_matches(cell1, cell2, key):
+    return cell1[key] == cell2[key]
         
 def get_from_coords(world, x, y):
     if y >= 0 and x>= 0 and y < len(world) and x < len(world[y]):
@@ -76,29 +78,47 @@ def get_adjacent(world, x, y):
 
 
 def group_terrain(world):
-    groups = [[], []]
+    terrain = []
+    to_visit = []
     for y in range(world_h):
         row = []
         for x in range(world_w):
             cell = world[y][x]
-            terrain = {
+            cell_with_details = {
                 "v": cell,
                 "x": x,
-                "y": y
+                "y": y,
+                "type": LAND  if cell > water else WATER
             }
-            if cell > water:
-                groups[0].append(terrain)
-            else:
-                groups[1].append(terrain)            
-    for group in groups:
-        sub_group_id = 1
-        for i, cell in enumerate(group):
-            if i == 0:
-                cell["group_id"] = sub_group_id
-            elif 
+            row.append(cell_with_details)
+            to_visit.append(cell_with_details)
+        terrain.append(row)
 
-    print(groups)
-    return groups
+    visited = []
+    def lets_walk(w, x, y, visited, group_id):
+        cell = get_from_coords(w, x, y)
+        cell["group_id"] = group_id
+        visited.append(cell)
+        to_visit.remove(cell)
+        
+        north, east, south, west = get_adjacent(w, x, y)
+        if north and not north in visited and terrain_matches(cell, north, "type"):
+            lets_walk(w, north["x"], north["y"], visited, group_id)
+        if east and not east in visited and terrain_matches(cell, east, "type"):
+            lets_walk(w, east["x"], east["y"], visited, group_id)
+        if south and not south in visited and terrain_matches(cell, south, "type"):
+            lets_walk(w, south["x"], south["y"], visited, group_id)
+        if west and not west in visited and terrain_matches(cell, west, "type"):
+            lets_walk(w, west["x"], west["y"], visited, group_id)
+
+    group_id = 0
+    while len(to_visit) > 0:
+        lets_walk(terrain, to_visit[0]["x"], to_visit[0]["y"], visited, group_id)
+        group_id += 1
+
+    print(group_id)
+
+    return terrain
 
 def add_home(world):
     print("Choosing home location")