They're Cariads, from the Garth story "The Cloud of Balthus" by Jim Edgar and Frank Bellamy, which ran in the Daily Mirror from October 1971 to January 1972. It was reprinted in The Daily Mirror Book of Garth 1975 and by Titan Books in Garth Book One: The Cloud of Balthus in 1984. The one with the double-damond pattern is Lord Balthus himself.