Another example is the general case of three simultaneous equations with unspecified coefficients: To set up the flow graph, the equations are recast so each identifies a single variable by adding it to each side. For example: Using the diagram and summing the incident branches into "x1" this equation is seen to be satisfied. As all three variables enter these recast equations in a symmetrical fashion, the symmetry is retained in the graph by placing each variable at the corner of an equilateral triangle. Rotating the figure 120° simply permutes the indices. This construction can be extended to more variables by placing the node for each variable at the vertex of a regular polygon with as many vertices as there are variables. Of course, to be meaningful the coefficients are restricted to values such that the equations are independent and consistent.