In order to help secure the forthcoming cob walls to the stone stem wall, vertical rebar was placed in the stem-wall during construction of the wall. Lateral support was provided by the use of bamboo poles. Bamboo is both a strong, renewable natural resource; and was provided by a local grower. For curved corners, short pieces of rebar were hand-bent and secured to the vertical rebar using wire.
Also note that the stone stem wall is concave at the top so that the cob mix will 'key' into the wall for additional lateral stability.