Bruise

I noticed this bruise on my leg this morning and realised I had absolutely no idea how I got it. I do get quite a few bruises - usually traceable back to sitting with my legs, arms, whatever pressed up against a table leg or similar. I was thinking about this in relation to my work - it obviously made me think about marks left behind by a touch - but also about how we hear/ feel/ see lots of things without ever registering them and that one of the things which interests me is drawing attention to these small things. Once something has registered it is very difficult to ignore again, for example every time I notice a bruise it will trigger this train of thought. I was thinking it would be really interesting to produce a series of sounds which were not normally noticed (e.g. pencil marks on a surface) and turn them into downloadable ring-tones or similar so that they went from invisible to visible?