William Wrighte - Grotesque Architecture (1790)
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A guide to what today would probably be called follies though these "plans" don't seem very helpful to me. In any case here are some huts, grottos, hermitages and "rustic seats" that can be built with "flints, irregular stones, rude branches, and roots of trees".
I can't find anything about Wrighte - the name wasn't uncommon and though the book went into several editions there doesn't seem to have been much written about its author.