Illuminated logos and brand labels are on trend and are often used as part of a welcome scenario or, as in earlier Apple MacBooks, simply to delight users. Aside from these subtle beneficial effects, a light-up brand logo can also have other, more practical functions: One example is the illuminated BWT logo, which is activated by a proximity sensor in the AQA perla 4.0 water softening unit; when the light is blue, it indicates the device is working properly. If the logo turns yellow, it tells the user that action needs to be taken, while red indicates a fault if the device has stopped working properly. This is a simple but very useful function to assist communication between user and product, all made possible by an illuminated logo with no other components required.