The Contractor's Tool Belt

I made an interesting find on a jobsite a little while ago.  I discovered a Contractor’s tool I had not seen before.  I had often wondered how Contractors replicated the many curves that we, the designers, sweat and fret over on paper and in the computer.  The center to a radius is sometimes located twenty to thirty feet from the curve, in the next room or even outside of the building.  What fabulous, computer guided set of French Curve tools the Contractor must require for such a task.  We must be talking laser levels and GPS, right?
High Precision Curve Making Tool
I don’t mean to expose the “man behind the curtain” or anything.  But a broken pen taken from a bank, some electrical tape and a bent wire are used to create our graceful curves and detailing.  Just goes to remind you that we do not control the means and methods of those performing the work.