Fan, diamond, and rectangle shapes are combined in these systems. The fan in the base area supports the branching of the plant and can, if necessary, conceal the lower area later. Because aesthetic concerns-- such as in the case of the fan forms (6000)-- do not apply, such combination forms fit on almost every wall. With a little support, they offer considerable rope 'density' ...are therefore inexpensive and suitable for many plants, except strong twiners, like wisteria. Supportive details can be found in the sections on climbing plants and planning.