To build a folly is essentially to do something a second time, something at an inopportune moment. That something is always the memory of something forgotten, about which we can paradoxically say "There it is again."
Follies were misunderstood, purposeless constructions. They were often only small, extravagant gestures in a garden, easily whisking off the imagination to distant lands, a sort of time capsule built to awaken the memory and induce surprise in passers-by. They marked locations, organized secondary paths in a park, or simply predicted the arrival of better times—a demarcation, a sacred spot, a mysterious trail, a hill whose tragic rocky nature begged for a tower, a party, or the arrival of summer.
“It is demonstrably true that things cannot be other than as they are. For, everything having been made for a purpose, everything is necessarily for the best purpose.” — Professor Pangloss
A skilled draughtsman guides design conversations by selecting and emphasizing details in a way that computer programmes cannot. Ron Slade, author of Sketching for Engineers and Architects and a structural director at WSP in London, calls it “conversational drawing”. He notes how botany field guides are always based on detailed drawings rather than photographs — as much for what they leave out as for what they show. “Extraneous material that might exist in a photograph is eliminated. It may be important to pick out and illustrate particular areas and leave other parts in sketchy or broad outline.”