Highland units wore a doublet instead of a tunic. The strongly convex surfaces of the doublet and singlet face and (nearly) touch each other. This was instead covered by a doublet or by a codpiece. Underneath he wears a doublet of patterned material, probably silk damask. The Phrygian Sibyl appears to be a doublet of the Hellespontine Sibyl. It is the superposition of uniform flow, a doublet, and a vortex. The Higgs doublet couples to these fermions. It needs stronger curvature than the Fraunhofer doublet. The Royal Regiment of Scotland wears a short jacket called a "doublet", in Archer Green. Caesar is mentioned to be wearing an Elizabethan doublet instead of a Roman toga. Some roots, particularly those with doubled consonants, exhibit stress on both vowels flanking the doublet. Michelangelo paid Arcadelt with a piece of satin suitable for making into a doublet. These pairs, called a doublet, are often close semantically. Formal is white tie and requires a Regulation Doublet or higher. The spectrum would have two signals, each being a doublet.