1971 Marbrie (Trial/One-off ? )

A modern marbrie was first introduced with the 2nd Annual Limited Editions in 1971. This one was possibly a trial or a commemorative because its special feature is that the red & green "swags" have been “combed” to the centre of each of the 4 quadrants.
Signed with a red/white SL1971 date cane. Polished concave base; broad basal rim.