This article describes software for granular synthesis of sound. The software features a graphical interface that enables easy creation and modification of sound clouds by deterministic fractal organization. Output sound clouds exist in multidimensional parameter–time space, and are constructed as a micropolyphony of statements of a single input melody or group of notes. The approach described here is an effective alternative to statistical methods, creating sounds with vitality and interest over a range of time scales. Standard techniques are used for the creation of individual grains. Innovation is demonstrated in the particular approach to fractal organization of the sound cloud and in the design of a smart interface to effect easy control of cloud morphology. The interface provides for intuitive control and reorganization of large amounts of data.