the Marx #308 tunnel is described in Greenberg Vol II as... "Two-piece lithographed metal, mottled red and green patches on yellow, similar to army tanks." because of this comment and perhaps their inclusion in some army sets (? ... citation needed), i have always heard collectors refer to this accessory as a the Marx "camouflage" tunnel...
but recently i was thinking about Louis Marx who lived in the Northeast, and what he may actually have had in mind...
whatcha think?