The clip-on lens assembly has a pair of lenses connected together by a uniquely shaped, spring-biased nose bridge wire that has a profile that substantially matches the profile of the nose bridge portion of a pair of eyewear. Some embodiments, responsive to an instruction specifying: a pattern source operand and a target source operand, compare each of m data elements of the pattern operand with each data element of the target operand. In certain example embodiments, the anti-etch layer is formed using at least one ion beam. The three observation models are combined by a cascade particle filter so that the specific subject in the low frame rate video or the object with abrupt motion can be tracked quickly and accurately. The baby bottle holder also is shaped to act as a handle allowing the infant child to easily grip the bottle; and can be used as a teething toy.