Ten things were created during the twilight of the first Sabbath-eve.
These were:--The well that followed Israel in the wilderness, the manna,
the rainbow, the letters of the alphabet, the stylus, the tables of the
law, the grave of Moses, the cave in which Moses and Elijah stood, the
opening of the mouth of Balaam's ass, the opening of the earth to
swallow the wicked (Korah and his clique). Rav Nechemiah said, in his
father's name, also fire and the mule. Rav Yosheyah, in his father's
name, added also the ram which Abraham offered up instead of Isaac, and
the Shameer. Rav Yehudah says the tongs also, etc.
THE TALMUD, _Psachim_, fol. 54, col 1.