An alert device, which is adapted for mounting to a valve of a pneumatic object, is capable of detecting any decrease in the interior pneumatic pressure of the pneumatic object and generating a warning signal immediately therefor. The glitter particles have an organic substrate and an optical interference structure on one or both sides of the organic substrate. In another embodiment, one or more of the mechanical reels has a transparent window at a location where a symbol would normally be present. The invention compares media items in the collection with the seed items and determines which media items are added into the playlist by computation of similarity metrics or values. The obtained data is mashed-up with the obtained presentation.