Companies such as Alphabet are looking beyond the digital to the physical world—with mixed results. Jack Nicas in The Wall Street Journal notes that Google delivery drones have been toppled by wind, self-driving cars are flummoxed by snow, and sensor-embedded threads for wearables snap under the pull of industrial looms.

“In software, programmers can control their environment,” Nicas writes. “The physical world is messy and unpredictable.”

He quotes Google director and early investor John Doerr as saying back in 2000, “The new economy is based on bits, not atoms,” but now atoms are reasserting themselves. Google Project Wing team has learned, for example, that drones that work in simulations might not work in the real world.

There have been some successes. Nicas reports that in September, a Project Wing drone delivered some burritos from a food truck over a closed field to some Virginia Tech staffers and students a few hundred feet away.

If it’s any consolation to engineers struggling with the physical world, software itself might become more difficult as Moore’s Law stalls and designers look for alternatives to von Neumann architectures. At the International Test Conference last month, Rob A. Rutenbar, Bliss Professor and Head, Department of Computer Science, University of Illinois at Urbana-Champaign, said, “We have thus far been blessed with opportunity to ride Moore’s Law, but we urgently need a new plan because it’s about to give up the ghost.” Read about his new plan here.