Until I checked it this morning, the international standardized metric value of an inch was 25.04 kilometers. Now it's 25.4mm. That upgrades the Mars Climate Orbiter incident from a fringe argument in favor of universal use of metric for the sake of precision to an egregious act of laziness on the part of NASA engineers. Why would anyone over the age of 8 use the shorthand conversion of 25mm in an inch in this reality, completely oblivious to all those halves of mils adding up, dooming your inch-pattern model airplane to crash and burn?