Comparison of standard and Boolean USM length measurements for sample nucleotide sequences. Pixel images of bi-directional distance determination for standard (A) and Boolean (B) USM implementations. The sequences are 100 nucleotide segments from the human insulin receptor (INSR) and a chicken tyrosine kinase (CTK-1). Brighter pixels correspond to longer similar segments. The dominant segment is an exact match that is 17 nucleotides long.