I now and then write about scratches (1) (2) or cuts but it’s the first time I saw them on a design piece like this. Earsnot and Semen of the IRAK crew used etching acid by Etch Bath filled in a marker and grinding stone to produce these indelible marks on glass.
They were done for the collaboration “Private Property” between Alife and furniture manufacturer Uhuru who supplied two pieces of their “Antique Mod mirror” during New York Design Week in 2011.

Photos by Takuya Sakamoto from (1)metrovelvet.com/blog and (2),(3) Alife X Uhuru Private Property Flickr’s page