diff --git a/crafts.lua b/crafts.lua
index 02aaf59..29a9eef 100644
--- a/crafts.lua
+++ b/crafts.lua
@@ -157,9 +157,9 @@ minetest.register_craftitem("mobs:saddle", {
 minetest.register_craft({
 	output = "mobs:saddle",
 	recipe = {
-		{"mobs:leather", "mobs:leather", "mobs:leather"},
-		{"mobs:leather", items.steel_ingot, "mobs:leather"},
-		{"mobs:leather", items.steel_ingot, "mobs:leather"}
+		{"group:leather", "group:leather", "group:leather"},
+		{"group:leather", items.steel_ingot, "group:leather"},
+		{"group:leather", items.steel_ingot, "group:leather"}
 	}
 })
 
diff --git a/spawner.lua b/spawner.lua
index 0ec0101..1dd9c88 100644
--- a/spawner.lua
+++ b/spawner.lua
@@ -10,6 +10,7 @@ local function is_player(player)
 	end
 end
 
+local square = math.sqrt
 
 local get_distance = function(a, b)