Wednesday, December 27, 2017

Automated Tetris

Following complaints that Amazon sometimes uses excessively large boxes for packing small items, the following claim appeared on Reddit.

"Amazon uses a complicated software system to determine the box size that should be used based on what else is going in the same truck and the exact size of the cargo bay. It is playing automated Tetris with the packages. Sometimes it will select a larger box because there is nothing else that needs to go out on that specific truck, and by making it bigger, it is using up the remaining space so items don't slide around and break. This actually minimizes waste and is on the whole a greener system. Even if for some individual item it looks weird. It's optimizing for the whole, not the individual." [source: Reddit via @alexsavinme]

Attached to the claim is a link to @willknight's 2015 article about Amazon's robotic warehouses. The article mentions the packing problem but doesn't mention the variation of box sizes.

The claim quickly led to vigorous debate, both on Reddit and on Twitter. Here are a selection of the argument and counter-arguments.


  • Suggesting that the Reddit claim was based on a misreading of the MIT article.
  • Asserting that people working in warehouses (Amazon and other) were unaware of such an algorithm. (As if this were relevant evidence.)
    • Evidence that equally sophisticated algorithms are in use at other retailers and logistics companies. (Together with an assumption that if others have them, Amazon must definitely have them.)
    • Evidence that some operational inefficiencies exist at Amazon and elsewhere. (What, isn't Amazon perfectly optimized yet?)
      • Providing evidence that computer systems would not always recommend the smallest possible box. For example, this comment: "At Target the systems would suggest a size but we could literally use whatever we wanted to. I constantly put stuff in smaller boxes because it just made so much more sense." (Furthermore, the humans being able to frustrate the intentions of the software.)
      • Suggesting that errors in box sizes are sometimes caused by mix-up of units - one item going in a box large enough for a dozen.
      • Pointing out that the solution described above would only work for transport between warehouses (where the vehicle is full for the whole trip) but wouldn't work for "last mile" delivery runs (where the vehicle becomes progressively more empty during the trip).
      • Pointing out that the "last mile" is the most inefficient part of the journey. (But this doesn't stop retailers looking for efficiency savings earlier in the journey.)
      • Pointing out that there were more efficient solutions for preventing packages shifting in transit - for example, inflatable bags.
      • Pointing out that an overlarge box merely displaces the problem - the item can be damaged by sliding around inside the box.
      • Complaining about the ethics, employment policies and environmental awareness of Amazon.
      • Denigrating the intelligence and diligence of the workers in the Amazon warehouse. (Lazy? Really?)

      Some people have complained that as the claim is evidently false, it counts as fake news and should be deleted. But it is certainly true that retailers and logistics companies are constantly thinking about ways of reducing packaging and waste, and there are several interesting contributions to the debate, even if some of the details may not quite work.

      It's also worth noting that the claim is written in a highly plausible style - that's just how people in that world would talk. So maybe someone has come across a proposal or pilot or patent application along these lines, even if this exact solution was never fully implemented.

      Some may doubt that such a solution would be "greener on the whole". But any solution architect should get the principle of "optimizing for the whole, not the individual". (Not always so easy in practice, though.) 



      Will Knight, Inside Amazon’s Warehouse, Human-Robot Symbiosis (MIT Technology Review, 7 July 2015)

      Wikipedia: Packing Problems

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