diff --git a/island/generators.ts b/island/generators.ts
index 11c46e7..e2037ac 100644
--- a/island/generators.ts
+++ b/island/generators.ts
@@ -13,9 +13,7 @@ export const SMALL_MOUNTAIN: LobeGeneratorConstructor =
   (islands: IslandGrid, basePos: number) => () => {
     const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
 
-    const edgeTiles = islandTiles.filter(
-      (pos) => islands.data[pos] == WATER || islands.data[pos] == BEACH
-    );
+    const edgeTiles = islandTiles.filter((pos) => islands.data[pos] <= BEACH);
     islands.dropWithin(edgeTiles);
 
     const mountainTiles = islands.floodSearch(
@@ -44,7 +42,7 @@ export const SMALL_BEACH: LobeGeneratorConstructor =
   (islands: IslandGrid, basePos: number) => () => {
     const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
 
-    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
+    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] <= WATER);
     islands.dropWithin(shoreTiles);
 
     return true;
@@ -59,7 +57,7 @@ export const BIG_BEACH: LobeGeneratorConstructor = (
   return () => {
     const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
 
-    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
+    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] <= WATER);
     islands.dropWithin(shoreTiles);
     dropped++;
 
@@ -74,7 +72,7 @@ export const SCATTERED_FOREST: LobeGeneratorConstructor =
     const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
 
     // grow shore
-    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
+    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] <= WATER);
     islands.dropWithin(shoreTiles);
 
     // seed beach
@@ -98,7 +96,7 @@ export const CONTIGUOUS_FOREST: LobeGeneratorConstructor =
     const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
 
     // grow shore
-    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
+    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] <= WATER);
     islands.dropWithin(shoreTiles);
 
     // seed beach
@@ -122,7 +120,7 @@ export const HILLY_FOREST: LobeGeneratorConstructor =
     const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
 
     // grow shore
-    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
+    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] <= WATER);
     islands.dropWithin(shoreTiles);
 
     // seed beach
@@ -150,7 +148,7 @@ export const ERODED_BEACH: LobeGeneratorConstructor =
   (islands: IslandGrid, basePos: number) => () => {
     const islandTiles = islands.floodSearch(basePos, (tile) => tile > WATER);
 
-    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] == WATER);
+    const shoreTiles = islandTiles.filter((pos) => islands.data[pos] <= WATER);
     islands.dropWithin(shoreTiles);
 
     // erode
diff --git a/island/grid.ts b/island/grid.ts
index 50b34aa..ed2697c 100644
--- a/island/grid.ts
+++ b/island/grid.ts
@@ -21,7 +21,7 @@ export class IslandGrid {
   done = false;
 
   constructor(public width: number, public height: number, seed: number) {
-    this.data = Array(width * height).fill(0);
+    this.data = Array(width * height).fill(-1);
     this.rng = mulberry32(seed);
 
     const islandBag = this.shuffle([