efficiency is such a tricky subject. What is an efficient system, take for instance engines, some might say a very complex engine that gets the best output per

efficiency is such a tricky subject. What is an efficient system, take for instance engines, some might say a very complex engine that gets the best output per unit input is very "efficient" however others would claim a simple two stroke engine is more "efficient" from a design perspective. In that sense "efficient" and this metric are at odds as the more complex the thing gets the more "efficient" it is.