wire pieces will be 'lit' when it receives power (power propagation not implemented)

src/org/dyn4j/geometry/Vector2.kt

@@ -536,6 +536,13 @@ class Vector2 {
     val isZero: Boolean
         get() = Math.abs(this.x) <= Epsilon.E && Math.abs(this.y) <= Epsilon.E
 
+    /**
+     * Returns false if this [Vector2] is the zero [Vector2].
+     * @return boolean
+     */
+    val isNotZero: Boolean
+        get() = !isZero
+
     /**
      * Negates this [Vector2].
      * @return [Vector2] this vector