Anything that runs out to a point.

Then the devil taketh him up into the holy city, and setteth him on a PINNACLE of the temple, and saith unto him, If thou be the Son of God, cast thyself down: for it is written, He shall give his angels charge concerning thee: and in their hands they shall bear thee up, lest at any time thou dash thy foot against a stone. ( Matthew 4:5 )