  Skyrmions are important in topological quantum field theory for being soliton
solutions of a nonlinear sigma model and in information technology for their
attractive applications. Skyrmions are believed to be circular and stripy spin
textures appeared in the vicinity of skyrmion crystals are termed spiral,
helical, and cycloid spin orders, but not skyrmions. Here we present convincing
evidences showing that those stripy spin textures are skyrmions, "siblings" of
circular skyrmions in skyrmion crystals and "cousins" of isolated circular
skyrmions. Specifically, isolated skyrmions are excitations when skyrmion
formation energy is positive. The skyrmion morphologies are various stripy
structures when the ground states of chiral magnetic films are skyrmions. The
density of skyrmion number determines the morphology of condensed skyrmion
states. At the extreme of one skyrmion in the whole sample, the skyrmion is a
ramified stripe. As the skyrmion number density increases, individual skyrmion
shapes gradually change from ramified stripes to rectangular stripes, and
eventually to disk-like objects. At a low skyrmion number density, the natural
width of stripes is proportional to the ratio between the exchange stiffness
constant and Dzyaloshinskii-Moriya interaction coefficient. At a high skyrmion
number density, skyrmion crystals are the preferred states. Our findings reveal
the nature and properties of stripy spin texture, and open a new avenue for
manipulating skyrmions, especially condensed skyrmions such as skyrmion
crystals.
