evidence: According to this bit of online lore, the colored squares or rectangular bars found on the crimp at the closed end of toothpaste tubes signify the composition of the product contained therein: whether its ingredients are "natural" or "chemical," and whether the toothpaste includes "medicine." (These terms are really too vague to be useful, as even "natural" products are made up of "chemicals," and "medicine" is too non-specific a term to be informative.) However, those colored squares on the crimps of those tubes have nothing to do with the formulation of the toothpaste inside. They're an artifact of the manufacturing process known as "eye marks" or "color marks," printed marks that can be read by light beam sensors and typically identify where product packaging is to be cut or folded as connected units stream through machinery at high speed: [...] The best way to ascertain the composition of a given brand of toothpaste is by reading the ingredients information printed on the toothpaste box and/or tube.