This invention is a "four-direction moving" structure that can move in all four directions without turning first. It contains two groups of wheels that are arranged perpendicular to one another, i.e. four rows of wheels form a quadrate. Within each group, the wheels turn in the same direction. The conventional circular wheels are replaced with circular eccentric or elliptical or noncircular (e.g. polygonal) wheels so that one group of wheels will not impede movement when the other group of wheels is turning by virtue of the longer diameter of the turning wheels.