diff --git a/src/sagotmx/tmx_struct.h b/src/sagotmx/tmx_struct.h
index 30d5314..e9b5723 100644
--- a/src/sagotmx/tmx_struct.h
+++ b/src/sagotmx/tmx_struct.h
@@ -531,6 +531,18 @@ inline uint32_t getTileFromLayer(const TileMap& m, const TileLayer& l, int x, in
 	return global_tile_id;
 }
 
+inline void setTileOnLayerNumber(TileMap& m, int layer_number, int x, int y, uint32_t tile) {
+	size_t tile_index = (m.height*y+x)*sizeof(uint32_t);
+	TileLayer& l = m.layers.at(layer_number);
+	if (tile_index > l.data.payload.size()-sizeof(uint32_t) ) {
+		throw SagoTiledException("ERROR: setTileOnLayerNumber called with coordiantes out-of-bound. Called with (%d, %d). Limit (%d, %d). Or the layer is corrupt. "
+				"Reported number of tiles in layer: %ld", x, y, m.width-1, m.height-1, l.data.payload.size()/sizeof(uint32_t));
+	}
+	std::string& data = l.data.payload;
+	uint32_t* dp = reinterpret_cast<uint32_t*> (&data[tile_index]);
+	*dp = tile;
+}
+
 }  //tiled
 }  //sago
 
diff --git a/src/saland/Game.cpp b/src/saland/Game.cpp
index d2519ee..9b3c1ab 100644
--- a/src/saland/Game.cpp
+++ b/src/saland/Game.cpp
@@ -341,6 +341,12 @@ void Game::ProcessInput(const SDL_Event& event, bool& processed) {
 			}
 			processed = true;
 		}
+		if (event.key.keysym.sym == SDLK_w) {
+			int layer_number = 2; //  Do not hardcode
+			uint32_t tile = 485;
+			sago::tiled::setTileOnLayerNumber(data->world.tm, layer_number, data->world_mouse_x/32, data->world_mouse_y/32, tile);
+			data->world.init_physics(data->physicsBox);
+		}
 	}
 }
 
diff --git a/src/saland/model/World.cpp b/src/saland/model/World.cpp
index f6ded4e..87a243d 100644
--- a/src/saland/model/World.cpp
+++ b/src/saland/model/World.cpp
@@ -73,7 +73,7 @@ static b2Body* AddStaticBody(b2World* world) {
 	return body;
 }
 
-static void AddStaticTilesToWorld(b2World* world, const sago::tiled::TileMap& tm, const sago::tiled::TileLayer& layer) {
+static b2Body* AddStaticTilesToWorld(b2World* world, const sago::tiled::TileMap& tm, const sago::tiled::TileLayer& layer) {
 	b2Body* body = AddStaticBody(world);
 	for (int i = 0; i < tm.height; ++i) {
 		for (int j = 0; j < tm.width; ++j) {
@@ -84,15 +84,14 @@ static void AddStaticTilesToWorld(b2World* world, const sago::tiled::TileMap& tm
 			AddRectToBody(body, i*32.0f, j*32.0f, 32.0f, 32.0f);
 		}
 	}
+	return body;
 }
 
-void World::init(std::shared_ptr<b2World>& world) {
-	this->physicsWorld = world;
-	std::string tsx_file = sago::GetFileContent("maps/terrain.tsx");
-	std::string tmx_file = sago::GetFileContent("maps/sample1.tmx");
-	ts = sago::tiled::string2tileset(tsx_file);
-	tm = sago::tiled::string2tilemap(tmx_file);
-	tm.tileset.alternativeSource = &ts;
+void World::init_physics(std::shared_ptr<b2World>& world) {
+	for (b2Body* b : managed_bodies) {
+		world->DestroyBody(b);
+	}
+	managed_bodies.clear();
 	const std::vector<sago::tiled::TileObjectGroup>& object_groups = tm.object_groups;
 	for (const auto& group : object_groups) {
 		for (const auto& item : group.objects) {
@@ -100,7 +99,8 @@ void World::init(std::shared_ptr<b2World>& world) {
 				continue;
 			}
 			if (item.x > 0 && item.y > 0 && item.width > 0 && item.height > 0) {
-				AddStaticRect(physicsWorld.get(), item.x, item.y, item.width, item.height);
+				b2Body* bodyAdded = AddStaticRect(physicsWorld.get(), item.x, item.y, item.width, item.height);
+				managed_bodies.push_back(bodyAdded);
 			}
 		}
 	}
@@ -109,7 +109,18 @@ void World::init(std::shared_ptr<b2World>& world) {
 		if (layer.name != "blocking") {
 			continue;
 		}
-		AddStaticTilesToWorld(physicsWorld.get(), tm, layer);
+		b2Body* bodyAdded = AddStaticTilesToWorld(physicsWorld.get(), tm, layer);
+		managed_bodies.push_back(bodyAdded);
 	}
 }
 
+void World::init(std::shared_ptr<b2World>& world) {
+	this->physicsWorld = world;
+	std::string tsx_file = sago::GetFileContent("maps/terrain.tsx");
+	std::string tmx_file = sago::GetFileContent("maps/sample1.tmx");
+	ts = sago::tiled::string2tileset(tsx_file);
+	tm = sago::tiled::string2tilemap(tmx_file);
+	tm.tileset.alternativeSource = &ts;
+	init_physics(world);
+}
+
diff --git a/src/saland/model/World.hpp b/src/saland/model/World.hpp
index b92186d..47a53e7 100644
--- a/src/saland/model/World.hpp
+++ b/src/saland/model/World.hpp
@@ -32,10 +32,12 @@ class World {
 public:
 	World();
 	void init(std::shared_ptr<b2World>& world);
+	void init_physics(std::shared_ptr<b2World>& world);
 //private:
 	sago::tiled::TileSet ts;
 	sago::tiled::TileMap tm;
 	std::shared_ptr<b2World> physicsWorld;
+	std::vector<b2Body*> managed_bodies;
 };
 
 #endif /* WORLD_HPP */