Al is an absolute wealth of knowledge in all things rocky, (as well as a good few things besides), and oozes enthusiasm for his subject. His aim was to open our eyes to the landscape through which we passed, and I found it fascinating. He runs his company along these lines too, which can be found at https://hillsofhame.wordpress.com/, and I heartily recommend him if you would like to know a little more about what is below our feet and all around us, and how it came to look as it does today.
A little more workaday was looking at the path Al had built as part of a team in the late 90's, how it had fared through the ravages of time and many feet, the features that path builders employ to channel water, and indeed how much care is taken to reduce the possibility of injury to users. We use many miles of the fruits of someone's labour, and usually pay little heed to them - Al's explanations opened our eyes to the thought and effort that goes into them.
Finally, we just had a nice walk through a well-used but very pleasant part of the East Lothian countryside, our freshly-trained eyes spotting igneous rock and fault lines in abundance. We even saw a peregrine falcon, (Al's first in the Pentlands), giving a buzzard a right old going over with dramatic, swooping dives.
Thanks to everyone for their company, and Al for a good day out.