If you Google curved shingles there is a site for patented devices that curve shingles going back to 1887 -

Yes..thanks for the info..fills in a few gaps..so that roof is essentially some kind of asphalt shingle treatment, designed to simulate thatch...which just raises all kinds of further questions about how, exactly, it was done...some kind of heat-treatment during installation, maybe? ...no doubt the old guys who did the original roof back in 1917 have all Gone to Glory, as Grandma would say, but since the life of even the best asphalt shingles is finite we can reasonably assume this is probably not the original roof ...so somebody out there probably knows just exactly how this was done..

Thank you for that interesting information.

Very interesting roof..any ideas how that was done, with what material, and how, etc?

A very rare example of transition from Art Nouveau to Prairie Style in Bay Ridge, Brooklyn, NY. This mansion was build by J. Sarsfiled Kennedy in 1916-17 and reminds locals of Gingerbread House.