diff --git a/src/play_clj/physics.clj b/src/play_clj/physics.clj
new file mode 100644
index 0000000..1fe2a7b
--- /dev/null
+++ b/src/play_clj/physics.clj
@@ -0,0 +1,21 @@
+(ns play-clj.physics
+  (:require [play-clj.utils :as u])
+  (:import [com.badlogic.gdx.physics.box2d World]))
+
+(defn world*
+  ([]
+    (world* 0 0 true))
+  ([gravity-x gravity-y]
+    (world* gravity-x gravity-y true))
+  ([gravity-x gravity-y sleep?]
+    (World. (u/gdx-vector gravity-x gravity-y) sleep?)))
+
+(defmacro world
+  [gravity-x gravity-y & options]
+  `(let [object# (world* ~gravity-x ~gravity-y)]
+     (u/calls! ^World object# ~@options)
+     object#))
+
+(defmacro world!
+  [{:keys [^World world]} k & options]
+  `(u/call! ^World ~world ~k ~@options))
diff --git a/src/play_clj/utils.clj b/src/play_clj/utils.clj
index 05c3f4b..95c6335 100644
--- a/src/play_clj/utils.clj
+++ b/src/play_clj/utils.clj
@@ -1,6 +1,7 @@
 (ns play-clj.utils
   (:require [clojure.string :as s])
   (:import [com.badlogic.gdx.graphics.g2d TextureRegion]
+           [com.badlogic.gdx.math Vector2 Vector3]
            [com.badlogic.gdx.scenes.scene2d Actor]
            [com.badlogic.gdx.utils Array ArrayMap]))
 
@@ -67,6 +68,12 @@
      (.put amap k v))
    amap))
 
+(defn gdx-vector
+  ([x y]
+    (Vector2. x y))
+  ([x y z]
+    (Vector3. x y z)))
+
 ; java interop
 
 (defmacro call!