see the photo of the black marks on the paddle (3 on top, 3 on bottom), compare to
Otzi the ice man's tattoos: medical treatment for lyme disease arthritis
My diagnosis: the black marks refer to "flow", the power of water flowing (rapids, waterfalls, dams).
Compare: week(from wehsal-track-furrow)-furrow-perau(Malay canoe)-plow, shoe-last axe,
The agricultural arrival in southern Scandinavia thus appears sharp. Gradualist views of Late Mesolithic developments can be discounted despite the spread of shoe-last axes beyond the farming frontier. Western Norway presents a similar pattern: axes and ceramics were in circulation for over a millennium beyond the farming boundary.
This farming spread must have been by boat. There were no native aurochs on Zealand (Aaris-Sorensen 1980), so the early cattle at Akonge were definitely imported. Farther north, agriculture was probably carried by boat up the coasts, an easier method of travel than overland (see above). Baltic crossings would require longer open-water voyages than in the Cardial or LBK. Irish curraghs can, however, make substantial voyages and weather considerable seas (Hornell 1938, sec. 5:17–21), and a large one has even crossed the Atlantic (Severin 1978).
Old map legends may have similar symbols for river cataracts, canals etc.
Compare also to number systems ||| = = /// etc.