My Dad bought this stereo during a brief period when mp3s on CDs were a useful media source. The idea of mp3s on CD were quickly superseded by iPods and other portable mp3 players which could be plugged into a set of speakers. However, me and my sister had dismissed this stereo long before due to its utterly unusable interface.
The revolutionary ‘rotary navigation’ made skipping to the next track somewhat taxing - you have to spin the dial clockwise (and vice versa to go back a track). The dial is spring-loaded so that once it is turned clockwise, it returns to its neutral position and you can repeat to skip another track. However, this spring is so tight that skipping a track takes a great deal of effort and grip on the dial. The true horror of this design is realised when you insert an mp3 CD (the benefit of which is to hold hundreds of tracks) and try turning the dial hundreds of times to get to the desired track… I don’t think I ever got past 10!
When I accidentally bought the same toothbrush as my flatmate, I decided I needed to do something to my brush to let me know which one was mine and avoid the confusion (and horror) of using the wrong brush. I wrapped a piece of electrical tape around the handle, this acts both as a visual cue to differentiate between the two, but also as a tactile cue so that when one picks up the brush, it feels different in the hands - even if they are not looking at it.
This kind of tactile cue could be used with many other everyday objects to differentiate without the use of visual information. Bumps and textures could be used navigate a product or set of products - particularly useful for blind user groups, or applications where the eyes are otherwise occupied, for instance whilst driving.