hi all,
anyone know why this planes underwing looks like a patchwork quilt,

Click for high resolution image
from, Lockheed Hudson in WW11, by Andrew Hendrie, Airlife publishing.
just brought a copy of this book along with The Lockheed Twins, by Peter Marson, Air-Britain Publishing.
i also seek any other images of Hudsons, please don't tell me to Google, as i have done this until my Googles fell off!
what other books are available? what other internet site can i find stuff on, done British Pathe, and the Flight Archives.