One of the selling points for modular smartphones like Project Ara or the Puzzlephone is that they reduce waste. But little has been said about how discarded modules could be put to use. Finland's Circular Devices, the company developing the Puzzlephone, has now revealed its answer to that question: it's called the Puzzlecluster, and it's a scalable supercomputer.

The concept is pretty simple: when a Puzzlephone owner inevitably decides to upgrade their modular phone's "brain" (read: processor unit), the old module can be repurposed to power a versatile computer. With many different outdated smartphone CPUs combined, the cluster should have enough processing power to make the Puzzlecluster a useful addition to someone's business — and give the modules a new lease on life.

In addition to a traditional power supply, the concept calls for the case to be able to accept battery modules from the Puzzlephone as well, to maintain the system's heartbeat. Circular Devices says that the Puzzlecluster's "applications can range from research and data analysis, to rendering farms and in-house cloud services, as well as any other case that requires parallel computing." The initial illustrations show a small cube that can only accept a few modules at once, but multiple units could be combined together to create an even more powerful computer.

For now, the Puzzlecluster is just a concept — it seems to be little more than a few ideas on a whiteboard. But it's a good idea, and whether or not the Puzzlephone takes off, it's good to see that someone is thinking about what we can do with smartphone modules once they become outdated.