fix wall not reappearing on pause

src/components/wall.js

@@ -11,6 +11,10 @@ AFRAME.registerComponent('wall', {
     this.el.object3D.visible = false;
   },
 
+  play: function () {
+    this.el.object3D.visible = true;
+  },
+
   tock: function (time, delta) {
     this.el.object3D.position.z += this.data.speed * (delta / 1000);
     this.returnToPool();
@@ -19,6 +23,7 @@ AFRAME.registerComponent('wall', {
   returnToPool: function () {
     if (this.el.object3D.position.z < this.maxZ) { return; }
     this.el.sceneEl.components.pool__wall.returnEntity(this.el);
+    this.el.object3D.position.z = 9999;
     this.el.pause();
   },
 });