Forum:Measurement unit

OK, I'm not trying to offend anyone, it's just really bugging me. How did the convention of measuring units of measure (not units of destruction) on this site become 0.5 instead of 1? I mean a grid is, by conventional standards, an "x" by "x". With the lowest square on the grid being 1. How did this end up calling one square on the grid, 0.5 of a whatever???