Thirty –

Thirty

Shirt with 28.200 glass-head pins,
11 in x 11 in x 4 in, 2012
Shirt with 29.400 glass-head pins,
11 in x 11 in x 4 in, 2014

According to records from 1895, the symbol 30 used to indicate the last sheet—or line of copy—of a dispatch as a printer's and telegrapher's code .In similar fashion, in 20th century journalism , 30 came to be a traditional sign-off signal and slang word for "the end." (source: Online Etymology Dictionary)

Photos courtesy: Silvia Malagrino