DRAWING ON CONCRETE
At Peace Lutheran Church in Danville, CA, I drew a labyrinth on a concrete slab and also gave a one-day labyrinth training. The church was new and the landscaping just being installed.They had poured a new concrete slab some 44 feet in diameter, with expansion joints that formed an octagon. My job was to draw the Chartres labyrinth, which would be painted by their volunteer artist. I drew the labyrinth with indelible Sharpie® felt tip pens. That meant there was no room for error. Because I had to be extra careful, it took me about ten hours to draw the labyrinth.
Posts and plastic were constructed around the concrete to protect the
surface on which I was drawing from the sprinkler system. This is an arrid
area, green only by watering everything profusely.
I used the extra large Sharpies® which worked well except for one problem. The concrete wore down the tips. On the larger circles, I couldn't finish the circle before the tip was down to the body of the marker. There was plenty of ink, but no way to use it. I went through some two dozen pens.
All of the lines were drawn as two parallel lines, so that the artist could paint between them and thereby execute a perfect line. I made only one mistake, over-shooting a line by about half an inch, which I removed with a piece of sand paper. (The extraneous line in the second photo, lower right corner, is in a painted area. Not a mistake.)
Post script: This was done around 10 years ago. Now, we not only draw with Sharpies, we draw with saws that have diamond blades, cutting the pattern into the concrete. Even less room for error. And we have a machine that tapes parallel lines, making it easier to paint. The above descriptionr eminds me of the old days. now we have much more sophisticated techniques and tools.