a pennant, a banner
旙 centers on a flag-like cloth used for signaling or display: a pennant or banner.
旙 combines 方 (a flag or direction) with 番, which likely contributes the sound. The character is a variant of 幡, where 巾 (cloth) is replaced by 方, emphasizing the flag aspect.
The left side 方 suggests a flag, and the right side 番 looks like a numbered panel. Picture a numbered pennant fluttering in the wind.
For ヘン, imagine a hen-shaped pennant flapping on a pole: hen -> ヘン, and the banner waves like a hen's wing.