This church is totally destroyed due to fire. The pictures are from before the fire.
At the east side church in Porsgrunn (from 1760 CE), God’s name was not written the way we usually see it. Behind the altarpiece there were two large statues that represented Aaron and Moses. The statue of Moses was holding a stone slab with extractions of the ten commandments.
On this slab God’s name were written with the two Hebrew letters “YY”. On top of the name there is drawn a symbol that looks like the symbol for infinity.
The spelling YY can be due to a confusion between the Hebrew letters Y and W. God’s name was often shortened to YH, YW or just Y, in Hebrew writings. In writings found in Qumran you can see that the Hebrew letters Y and W are easy to confuse. The spelling YY is probably a misreading of the shortened spelling YW. After some time this spelling was also written YYY or YWY, or even YYYY. A papyrus of the Bible, from the third century CE has been found where God’s name is written YY.