highdio:

(Hadn’t seen this specific design detail written on yet, so)

Top image is by Antonio Lopez for Missoni, 1983.

Araki’s heavily influenced by and often directly references Lopez, so much so that the the triangle pattern on Missoni knits
featured in an ad campaign Lopez did for the designer found its way
onto Caesar’s headband, Jotaro’s signature double belts, and other
elements throughout Araki’s drawings.

Basically, they’re all wearing Missoni.