A system for finding a solution to a constrained optimization problem is disclosed. The inventors have found that this can be achieved by making the region which comprised the interface with domains adjoined to said IgSF domain in a larger fragment or a full IgSF protein, and which becomes exposed in the IgSF domain, more hydrophilic by modification. The tool engaging hexagonal shape includes six non-contiguous flats having rounded portions therebetween. This libraries can be used to study the role of specific amino acids in protein structure and function and to develop new or improved proteins and polypeptides such as enzymes, antibodies, single chain antibodies and catalytic antibodies. The synthesizer comprises a plurality of samples stored in a memory; a plurality of voices each comprising means for calculating an output using a plurality of samples selected from the plurality of samples stored in the memory; wherein a voice is active when calculating an output; wherein the number of samples selected by the means for calculating depends upon the number of active voices. A frequency disperser receives the output of the wavelength discriminator and provides a physical separation of output wavelengths of the broadband output.