English: Collage for security method of applying glitter nail varnish to computer screws on the reverse side of a Chromebook computer. Glitter nail varnish produces unrepeatable patterns that are destroyed through unscrewing. Therefore, if you photograph the patterns, you can detect whether someone has unscrewed the screws since the time of your photograph, because the original patterns are destroyed through unscrewing; you can simply compare the current patterns with those in your photograph.