Here it is, Margaret!
The promised instructions are below. I used five 2" x 8" x 12' redwood or cedar for each box. One of the 12' boards was cut into four pieces for the two ends. I used 4" x 4" treated posts to tie the corners and support the middles. After building each one it was lifted and carried to a leveled spot, filled with compost and planted. In the bottom picture you can see some of my 5th-grade students who had put the last one together. They are very easy to make, obviously!
Evan, James and Cody relax after after the thrill of a"Mission Accomplished".