I aim to go for a walk every day. Once a week, I meet up with one or other of my friends, as permitted by law.

The problem is that we are running out of places to go. By Monday of this week we literally reached the point of staring at brick walls – albeit, again literally, the walls of Jericho. And noticing how interesting they are.

What appeared to be a single Georgian terrace was, on closer inspection, a series of blocks which had clearly been put up by different builders. One obvious clue was that they were slightly different heights. The other was the different styles of brickwork. Some were plain, some used bricks for decorative features around doors and windows, whilst others combined different colours to create intricately patterned walls.

Some bricks had been subjected to grafitti – simple patterns or the inevitable initials, but on one house we discovered bricks that still bore the sharp stamp of the builder’s name and the date of manufacture. This simple mark seemed to create a link to the physical process of brickmaking – the unknown workman of 200 years ago who pressed the damp clay into a brick mold, stamped it and put it to dry before firing it – a process repeated hundred of times a day across the country wherever there was clay, water and wood.