Mysterious Vs in the bedrock

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Photo from the City of David website

A week ago, just in time for ABC Wednesday's V-Day, mysterious V-shaped carvings in the limestone beneath present-day Jerusalem were discovered during excavations.
Archaeologists of the dig are puzzled by the cuts in the rock in the City of David.
They are around 3,000 years old.

The Washington Posts says,
"Israeli diggers who uncovered a complex of rooms carved into the bedrock in the oldest section of the city recently found the markings: Three "V'' shapes cut next to each other into the limestone floor of one of the rooms, about 2 inches (5 centimeters) deep and 50 centimeters long. There were no finds to offer any clues pointing to the identity of who made them or what purpose they served."

Now this is where YOU come in!
If you have seen anything similar anywhere in the world, the archaeologists ask you to contribute that knowledge and help solve the mystery.

Go to the City of David site here and click on the photo to leave your answer.

Or if we just want to have fun and think of funny uses, you can write them in my comments section.
Over 20,000 have replied (not to me!).
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For the full story and more photos see
AP article in Washington Post or the Jerusalem Post article.

See ideas about the Vs at Todd Bolen's BiblePlaces Blog, e.g. one of his readers, A.B. Crysler, suggested this:
"The grooves in the limestone were used by the fullers to whiten clothes. II Kings 18:17 - ...they came and stood by the conduit of the upper pool, which is in the highway of the fuller's field. See also Isaiah 7:3 and 36:2."

I had to look up the word "fuller." It means a workman who fulls (cleans and thickens) freshly woven cloth.

OK, good luck!
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UPDATE: More speculation from Tom Powers here in Jerusalem
UPDATE 2: At the City of David archaeology conference last night, Sept. 7, 2012, they said that 75,000 answers or speculations were received from all over the world about the mysterious Vs.
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