I meant to look up about the definition of crinkle crankle walls. They’re one brick thick, built in curves because if they were built in a straight line, they could easily be pushed over – or topple of their own accord; and they normally face south (as they do at West Horsley) and were used for growing fruit:-
| Charles | Saumarez | Smith | 
They also maximise the optimal (south-facing) growing space for wall fruit
Many superb examples in Suffolk.
Hogarth would have approved!
I’ve always enjoyed calling them crinkum crankum walls which may have come from John Aubrey’s Brief Lives as performed by Roy Dotrice nearly half a century ago.
Looking up the etymology in the OED, the description of walls as crinkle crankle looks surprisingly recent (first recorded use in the Times in 1962). Charles
I think the West Horsley Place wall is early 18th century but most are late 18th or early 19th century. French Loyalists are said to have built some of the serpentine walls in Hampshire during the Napoleonic Wars