This group is composed of geometric shapes with a fairly rigorous basic structure. Some motifs, composed of plaid patterns and other motifs found especially in neckwear, are classically and unmistakably Scottish. Simple squares and lines are also in evidence. In some patterns, the geometric shapes lock together to produce bizarre optical effects: such patterns are referred to as “optical patterns”. We also find other themes, such as the spiral and circle, which have specific meditative and contemplative connotations.