Rule Free: LED Pen Ruler Traces Distances, Measures Curves

For point-to-point measurements along a straight line, the answer has long been obvious to architects and engineers. But in a world with increasingly unusual built forms, not to mention mapped courses that are not always narrowly linear, this neat concept design offers a slim and elegant solution.

http://dornob.com/rule-free-led-pen-ruler-traces-distances-measures-curves/