diff --git a/ts/Led.ts b/ts/Led.ts
index 774687a..8168908 100644
--- a/ts/Led.ts
+++ b/ts/Led.ts
@@ -161,6 +161,12 @@ export class Leds extends THREE.Object3D {
     /** Whether we need to show the lines of the leds. */
     showLines: boolean;
 
+    /** A little light to be turned on when all leds are off, to show depth. */
+    light: THREE.PointLight;
+
+    /** Array of all the leds of the setup. */
+    leds: Array<Led>;
+
     /**
      * Create a set of leds from their configuration.
      */
@@ -169,9 +175,15 @@ export class Leds extends THREE.Object3D {
 
         this.showLines = showLines;
         this.currentLedIndex = null;
+        this.light = new THREE.PointLight(0xffffff, 1000);
+        this.add(this.light);
+
+        this.leds = [];
 
         for (let ledInfo of calibration.leds) {
-            this.add(new Led(ledInfo, calibration.spheres));
+            let led = new Led(ledInfo, calibration.spheres);
+            this.add(led);
+            this.leds.push(led);
         }
     }
 
@@ -181,21 +193,23 @@ export class Leds extends THREE.Object3D {
      */
     toggle(led: Led): void {
         // If the specified led is the one on.
-        if (this.currentLedIndex !== null && led === this.children[this.currentLedIndex]) {
+        if (this.currentLedIndex !== null && led === this.leds[this.currentLedIndex]) {
             this.currentLedIndex = null;
             led.turnOff();
+            this.light.visible = true;
             return;
         }
 
-        for (let index = 0; index < this.children.length; index++) {
-            let child = <Led> this.children[index];
-            if (led === this.children[index]) {
+        for (let index = 0; index < this.leds.length; index++) {
+            let child = this.leds[index];
+            if (led === this.leds[index]) {
                 child.turnOn(this.showLines);
                 this.currentLedIndex = index;
             } else {
                 child.turnOff();
             }
         }
+        this.light.visible = false;
     }
 
     /**
@@ -203,7 +217,7 @@ export class Leds extends THREE.Object3D {
      */
     setShowLines(showLines: boolean): void {
         this.showLines = showLines;
-        for (let child of this.children) {
+        for (let child of this.leds) {
             if (child instanceof Led && child.on) {
                 child.lines.visible = showLines;
             }
@@ -216,15 +230,15 @@ export class Leds extends THREE.Object3D {
     next(): Led {
         if (this.currentLedIndex === null) {
             this.currentLedIndex = 0;
-            let led = <Led> this.children[0];
+            let led = this.leds[0];
             led.turnOn(this.showLines);
             return led;
         }
 
-        (<Led> this.children[this.currentLedIndex]).turnOff();
-        this.currentLedIndex = (this.currentLedIndex + 1) % this.children.length;
-        (<Led> this.children[this.currentLedIndex]).turnOn(this.showLines);
-        return <Led> this.children[this.currentLedIndex];
+        this.leds[this.currentLedIndex].turnOff();
+        this.currentLedIndex = (this.currentLedIndex + 1) % this.leds.length;
+        this.leds[this.currentLedIndex].turnOn(this.showLines);
+        return <Led> this.leds[this.currentLedIndex];
     }
 
     /**
@@ -233,13 +247,13 @@ export class Leds extends THREE.Object3D {
     previous(): Led {
         if (this.currentLedIndex === null) {
             this.currentLedIndex = 0;
-            (<Led> this.children[0]).turnOn(this.showLines);
-            return <Led> this.children[0];;
+            this.leds[0].turnOn(this.showLines);
+            return this.leds[0];
         }
 
-        (<Led> this.children[this.currentLedIndex]).turnOff();
-        this.currentLedIndex = (this.currentLedIndex + this.children.length - 1) % this.children.length;
-        let led = (<Led> this.children[this.currentLedIndex]);
+        this.leds[this.currentLedIndex].turnOff();
+        this.currentLedIndex = (this.currentLedIndex + this.leds.length - 1) % this.leds.length;
+        let led = this.leds[this.currentLedIndex];
         led.turnOn(this.showLines);
         return led;
     }