HOW A PYRAMID IS COLOURED

The square associated with a word is coloured according to its statistic.

For a given length (for a given stage), words of null statistics are coloured in white, whereas words of maximal statistics (positive and negative) are coloured in black. A uniform grey scale is used between these extrema. Each stage has its own grey scale.

However, to distinguish the negative statistics from the positive ones, the sign of the statistic of the upper word is put above the pyramid and the symbol O is added in the middle of the squares that correspond to subwords with statistic of opposite sign.

Finding words with unexpected frequencies in DNA sequences. 11.9.98 Page: 15 of 21