Archaeologists revealed today that they have discovered the first evidence in the UK of stonework painted with a pattern, suggesting Neolithic people enjoyed decorating.
It comes a week after the researchers, working at the Brodgar peninsula on Orkney, found plain painted stones thought to be around 5,000 years old at the spot.
The site, described as a possible Neolithic temple precinct, is between the Stones of Stenness and the Ring of Brodgar.
The latest discovery, made late yesterday afternoon, is a stone with a zigzag chevron pattern in red pigment.
It is thought the painted and decorated stones may have been used to enhance important buildings and may have been found in entranceways or areas of the building which had particular significance.
Nick Card, of the Orkney Research Centre for Archaeology (Orca), said: "I think the Neolithic people were no different from ourselves in that these were probably special structures which they felt should be adorned in different colours.
"There has been evidence at some other Neolithic sites where paint pots have been found with remains of pigment but they were considered to be for personal adornment rather than being used on a wider scale for the decoration of buildings.
"This is a first for the UK, if not for northern Europe.
"The use of colour in this particular way was always suspected but this is the first concrete evidence we have of it."
He added: "It is not Rembrandt though, it is pretty basic designs."
One of the stones found last week were painted purple-red, while the other was red and yellow.
The paint will now be analysed but it is thought it may have been made from hermatite mixed with animal fat and perhaps milk or egg.
The 6-acre (2.5-hectare) site – the size of around five football pitches – is being excavated by teams from across the world.
Last year a structure dubbed a Neolithic "cathedral" measuring 82ft (25m) long by 65ft (20m) wide with 16ft (5m) thick outer walls was discovered at the site.
Mr Card, director of the excavations at the site, said the latest discoveries were adding to their understanding of how later Stone Age people lived.
He said: "We've always suspected colours was a part of their world.
"This is adding to the dimension of the Neolithic that many archaeologists would have thought but there was no real evidence for.
"There is a buoyant mood on site and everyone feels it is a great privilege to be here."