Ancient Greek Technology Costs Jobs.

A True Story by Steve Baker.

We all know that advancements in technology can cost people their jobs. However, in the case of the building industry in Texas, the effect of introducing new technology can often be somewhat delayed.

Back in 1997, my new house was in the slow process of changing from plans on paper into bricks on concrete. One of the tasks that has to be done early on is to lay out the shape of the house accurately onto the land. My builder uses a sub-contractor to do that - and I had occasion to watch him work. He arrived in a beat up old pickup truck with four 'migrant workers' sitting in the back. In order to lay out the initial 'bounding rectangle' of the building, they follow this algorithm:

  • Measure a baseline for the long edge of the rectangle. Mark it with two stakes hammered into the ground and tie a length of nylon string between them.

  • Tie a second piece of string to one of the stakes and measure out the width of the rectangle along it. Eyeball the angle between the new edge and the baseline so it's roughly 90 degrees and you have an 'L' shape. One guy holds the string there.

  • Do the same at the other end of the baseline. Now you have a 'U' shape and two guys are holding the open ends of the strings.

  • Take a third piece of string - equal in length to the length of the rectangle. Give one end to each of the two guys who are already holding string. 'jiggle' them until all three strings are tight. You now have a parallelogram made of string, staked out at two corners.

  • Now take two long tape measures and with one guy standing at each corner of our parallelogram, position the tape measures along the two diagonals of the parallelogram. With two guys holding the tapes on the baseline stakes and the other two holding onto the strings and shouting out the lengths of the diagonals, they jiggle the two free points until all of the strings are tight and the two diagonals tape measures are reading the same lengths. This requires a lot of shouting, cursing and everyone telling everyone else which way to move.

  • Now they have a rectangle - so they bash in two more stakes and then level the whole thing with a really impressive-looking laser contraption.

Well, I watched this with some amusement - and asked why they didn't just calculate the length of the diagonal. The boss guy said that you couldn't do that - "It's impossible". I told him about Pythagoras' theorem. With the aid of a calculator (he didn't know what that funny 'square-root' key was for), I was able to show him how easy it is to calculate the length of the diagonal and do away with all the ugly 'jiggling'.

"Wow!" he said. Then he thought for a moment - "Now I'll only need three guys to hold the string!"...and fired one of them on the spot! I thought he was kidding - but the next day when they were measuring out the place for the garage, there was one less guy holding the string.

So, a 2,500 year old technological advance cost some poor guy his job.