On what principle or mnemotechnics the ideas were connected with the knots and colors we are totally in the dark; it has even been doubted whether they had any application beyond the art of numeration.[14-2] Each combination had, however, a fixed ideographic value in a certain branch of knowledge, and thus the _quipu_ differed essentially from the Catholic rosary, the Jewish phylactery, or the knotted strings of the natives of North America and Siberia, to all of which it has at times been compared.
The _wampum_ used by the tribes of the north Atlantic coast was, in many respects, analogous to the quipu.

In early times it was composed chiefly of bits of wood of equal size, but different colors.

These were hung on strings which were woven into belts and bands, the hues, shapes, sizes, and combinations of the strings hinting their general significance.

Thus the lighter shades were invariable harbingers of peaceful or pleasant tidings, while the darker portended war and danger.

The substitution of beads or shells in place of wood, and the custom of embroidering figures in the belts were, probably, introduced by European influence.
Besides these, various simpler mnemonic aids were employed, such as parcels of reeds of different lengths, notched sticks, knots in cords, strings of pebbles or fruit-stones, circular pieces of wood or slabs pierced with different figures which the English liken to "cony holes," and at a victory, a treaty, or the founding of a village, sometimes a pillar or heap of stones was erected equalling in number the persons present at the occasion, or the number of the fallen.
This exhausts the list.