The same letters, in the same, consecutive order, can be inserted somewhere into the words below to form new words or phrases. What are the letters and the new words?

PIES
PONE
CHIEF
THEIST
RESTED

HINT:
Three letters need to be inserted.

Answers:

The letters are ART:

PARTIES
PART ONE
CAR THIEF
THE ARTIST
RESTARTED 

Credit: NY Times Crossword
July 28, 2016
Adam G. Perl
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