GGG Ping.
What is the nearest town?
Being in Ireland, I thought you meant a pub...
I don't know how much credance to put on this because all of the other links say that they do not know the meanings of these carvings, but this makes sense to me.
The decoration at Newgrange plays an important role in representing the function of this site. The decoration n the kerbstone in front of the passage announces the purpose of the cairn. Newgrange was built with a passage which was oriented towards the rising position of the sun at the time of the winter solstice. At this time the sun reaches its most southerly rising position on the eastern horizon and reverses to start rising more northerly after the solstice.In effect the sun changes its direction of movement on the horizon at at the time of the solstice. The phenomenon of reversal of movement is graphically illustrated on the kerbstone in front of the passage (see picture above). The spiral ornamentation on this stone travels in two different directions separated by a vertical line. This mimics the revesal of movement of the sun at the time of the winter solstice, as represented by the movement of the sun's rays in the chamber of Newgrange. This spiral ornamentation is then repeated in other areas throughout the site.
The construction features of Newgrange provide the ideal environment in which to study the minute movement of the sun when it is at visual standstill at the time of the winter solstice. For the society which built it, Newgrange could have provided the earliest possible evidence that the sun had begun to reverse its movement along the eastern horizon, bringing with this change the promise of another growing season and the lengthening of daylight hours.
This naturally occurring phenomenon is celebrated in the unique ornamentation found at the site.
This is the best explanation I can find of the meaning of the spirals, although nobody really knows what they meant.