In the early part of the late Jōmon period, spatula-like implements were used to carve two or three lines to create parallel patterns of whirlpools and interlocking hooks on earthenware. Cord markings (jōmon) were sometimes added between the parallel lines to boost the pattern effect. In the later period, it became popular to draw big patterns, add cord markings inside, and carefully polish the outside. Moreover, toward the end of the late period, they would add clay beads like lumps to further decorate the vessel surface. These patterns were not just ornamental but were also expressions of prayer.