  We borrow the form of potential of the well-known kink-bearing $\varphi^4$
system in the range between its two vacua and paste it repeatedly into the
other ranges to introduce the periodic $\varphi^4$ system. The paper is devoted
to providing a comparative numerical study of the properties of the two
systems. Although the two systems are quite similar for a kink (antikink)
solution, they usually exhibit different behaviors throughout collisions. For
instance, they have different critical velocities, different results during
collisions, and a different rule in their quasi-fractal structures. Their
quasi-fractal structures will be studied in the disturbed kink-antikink
collisions as well. Hence, three types of scattering windows will be introduced
with respect to the incoming speed, the amplitude, and initial phase of the
internal mode, respectively. Moreover, a detailed comparative study of the
collisions between two kinks and one antikink will be done at the end.
