The Tik-Tok Easy Shop vending machine in Adams Morgan is meant to be a prototype of the robotic convenience store of the future. On Nov. 5, though, the machine was displaying some low-tech modifications: Its expansive glass front was cracked in two places, its insertion slots were covered by duct tape, and a handwritten sign on the touch screen announced, “Sorry For The Inconvenience For Your Safety We Are Out of Service. Twice we fix the glass. We Will Be Back Up And Serving You Again Tuesday afternoon. Once Again We Apologize For Any Inconvenience — Tiktok team.” A technician working on the machine on Nov. 11 explained that the Tik-Tok had sustained two assaults in recent weeks, one by a frustrated customer and another by rock-throwing passers-by. But the machine was not defenseless. Its security cameras, he said, had snapped pictures of the attacks. —Chris Shott