We dug three holes in our backyard to serve as molds for concrete tops of the mushrooms.
We then mixed batches of my special concrete/peat moss/ acrylic fortifier mixture, and poured it into the holes. We covered them up to protect the pieces from rain. After several days, we dug the pieces up and took them to Henry's house for further work. He cleaned them up, and applied bright colors to them.
After about three weeks for the concrete to cure, we assembled a crew of trusty trail volunteers to install the giant mushrooms along the trail.
We moved the pieces from Henry's van to wagons. Then our merry crew of workers and working dogs hawled the mushrooms for some distance to the site that Henry had selected for the installation.
Metal posts were sledged into the ground to support the mushrooms.
The mushrooms were installed over the posts.
Henry tested one mushroom out for stability and comfort.
Here is our working crew.