NY Times Crossword
November 8, 2007
Paula Gamache (adapted)

What do the three phrases below have in common?

PISTON ENGINE
FIRST ONE TO BLINK
UNFEELING NATURE

HINT:
Think of a three-word phrase that describes someone with an unfeeling nature.

Answer:

A person with an unfeeling nature might be said to have a heart of stone. The word STONE is hidden inside (at the heart of) the first two phrases:

piSTON Engine
firST ONE to blink