Well, guess what. They don't start out that way. Nope, they begin with a process called "de-turfing". This involves sliceing up wet, heavy turf (don't use the word sod here in the UK) and removing it.
And it could be so, but an alternate theory is that the cross cuts were to hold plaster, and that the stuff was used for walls.
More secrets lie below, stay tuned.
The awful Twice Brewed Pub Quiz is tonight. Last week's outing was too pathetic to chronicle.