In the initial position a linear piece stands on square X. It moves along any line and later the same piece moves along the same line in an opposite direction, passing through the square X.
The theme was proposed by Vitaly Medintsev for SuperProblem TT-149.
See also: Hesitation.
Jones, Christopher James Austin
Meinking, Daniel E.
F. Abdurahmanovic-60 JT, StrateGems, 2000