It's 3/4" CDX plywood, and I made them out of 16"x48" scraps I had laying around. The screws were leftover from a deck job I did (I'm a carpenter by trade). My only out-of-pocket expense for the project was the concrete mix and it averaged out to $4.00 per structure.
We had a good flood this past week with 4 1/2" of rain in one day.. so I'll get to see if they're still where I dropped them the next time I'm out!:confused:
I'm going to be disappointed if they aren't:(
Thanks for the kind words y'all.

