Adding conductive structure
The most important value for M5 is its stackable that it could link up multiple functional modules to fulfill your requirement, in a simple and elegant way. But M5 is yet not perfect. a pain point is in the stacking process, we use standard 2.54mm pin as the connector. You may ask that why not use some sort of touch spot? The reason is that it is hard to find those conponents with low cost and high quality(sustainable).
The conductive structure, set by bolt around the corners, has been tested，eventually fixed the problem and brings awesome user experience. XD