Tech: PDF file: how do photocopiers decide not to photocopy modern banknotes? ‘a geometric pattern … of five 1 mm large circles’. Fascinating stuff from Markus Kuhn, as usual! (via HackThePlanet)
(Things I found interesting recently.)
Tech: PDF file: how do photocopiers decide not to photocopy modern banknotes? ‘a geometric pattern … of five 1 mm large circles’. Fascinating stuff from Markus Kuhn, as usual! (via HackThePlanet)