In 1999, Kim and Lieber attached these entities to two independent electrodes to prepare the first near-atomic electromechanical system, which operated like a tweezer. (-5[1])Vertically aligned arrays of these entities (-5[1])are often generated using (15[1])a “tip-growth” or “base-growth” methodology. (15[1])Another of these entities (15[1])can be produced in a reaction involving a metal carbonyl catalyst at high pressure called the HiPCO (“hip-COE”) method. (15[1])The perimeter vector of these structures is commonly represented using (*) (m,n) (“m-comma-n”) lattice (10[1])index notation. (10[1])Depending on how they fold onto themselves, these structures can assume chiral, armchair, or zigzag (10[3])configurations. (-5[1])In the Russian-doll (10[1])model, (10[1])multi-walled examples of these structures comprise many concentric graphene layers. (10[1])For 10 points, (10[1])name these cylindrical allotropes (10[1])of (10[1])carbon. (10[2])■END■ (10[6]0[3])