Concertina Razor Wire

A connecting wire is represented by a straight line. It is usually made of copper and is provided with insulation to make electrical connections between two points.Symbol. Related Answer.The word concertina refers to a family of hand-held bellows-driven free reed instruments constructed according to various systems, which differ in terms of keyboard layout, and whether individual buttons (keys) produce the same (unisonoric) or different (bisonoric) notes with changes in the direction of air pressure.The English concertina is a unisonoric instrument which means that each button plays the same note on both the push and pull, like a piano accordion. It's most commonly used for playing English folk music, though some use it to play traditional Irish music to great effect.