A thumb tack is a flat, wide disc requiring one finger (or thumb) to imbed.
A pushpin has a tall, thinner body (with flanges on top and bottom) *requiring two 'fingers'.
A drawing pin was (25 years ago) a pushpin (shape) for securing drafting mylar (I'm sure it still is).

Depends on exactly you mean by vest. I know what yer sayin', Jimmy.