Have you ever tried to turn a #postcard on and off again?
No? Then get creative at 39c3 馃槉 I bring handmade stamps, UV-visible ink pads, and photons with the right wavelength 馃挕
Have you ever tried to turn a #postcard on and off again?
No? Then get creative at 39c3 馃槉 I bring handmade stamps, UV-visible ink pads, and photons with the right wavelength 馃挕