After a big rain storm last week.... problems.  Originally built this with just 3 balls of string!  I then drilled wooden dowls to the raised blocks on the surface. But it wasn't enough to support it all and noticed a drop to one side. So now I have had to use the wire that I found in the forest last summer as well.  Now it's stable, but  dissapointed to have to use wire again. I'm learning all the time.