We show that every solution of the following system of difference equations x n + 1 ( 1 ) = x n ( 2 ) / ( x n ( 2 ) − 1 ) , x n + 1 ( 2 ) = x n ( 3 ) / ( x n ( 3 ) − 1 ) , … , x n + 1 ( k ) = x n ( 1 ) / ( x n ( 1 ) − 1 ) as well as of the system x n + 1 ( 1 ) = x n ( k ) / ( x n ( k ) − 1 ) , x n + 1 ( 2 ) = x n ( 1 ) / ( x n ( 1 ) − 1 ) , … , x n + 1 ( k ) = x n ( k − 1 ) / ( x n ( k − 1 ) − 1 ) is periodic with period 2 k if k ≠ 0 ( mod 2), and with period k if k = 0 ( mod 2) where the initial values are nonzero real numbers for x 0 ( 1 ) , x 0 ( 2 ) , … , x 0 ( k ) ≠ 1 .