Ok, I've done up a temp. working plan for my H.G. Wells Martian lawn element...
Click on picture to enlarge.
I know there will be a lot of trouble shooting to do as it's made, but it's a start. There are a few rules I have for myself before creating it...
1) Keep it as lightweight as possible, sturdy and safe. Don't want it falling on anyone.
2) Budget: make it with as much of the "junk to make stuff" pile as I can with paint, etc. I already have trying not to spend any money on.
3) Remember to keep it sturdy and safe.
4) Big and imposing but fun.
5) Don't forget to make sturdy and safe.
6) Storage: try to make it so it can be disassembled and saved for next year.
7) Make it sturdy and safe.
8) Budget be damned if I need to buy things to make it sturdy and safe.