I started growing loofahs a few years ago - you know - loofahs. Those wonderful sponges you can buy for the shower. They grow like zucchini. You can eat them when they are little, use them as sponges in the bath or kitchen when dried, and they are beautiful flowering plants throughout the heat of the summer.
Anyway, last year Mr. Double Up and Junior Double Up built me some tunnels for my loofah crop. Technically, I think Junior Double Up built them and Mr. Double Up supervised, but that is immaterial - tunnels were created. The loofahs are loving them!!!!!