If regular convection rolls govern the development of tectonics of the Earth’s crust, we should see comparable formations at regular intervals on the surface. With a model of the convection cell system, this can of course be tested. Let us compare Iceland and Greenland:
The coasts at 66°N are exactly 30° apart, and the tectonics are mirrored so that the West Fjords of Iceland are aligned W34°S, but the fjords of Greenland are aligned W34°N. The main coast line is also mirrored, the West Fjords of Iceland follow the upper most convection cells to the NW (N31.4°E), but the outer coast of Greenland has the direction N31.4°W.
I have formerly compared the West Fjords with the west coast of Norway. The result is always a manyfold match. The interplay of different convection cell layers is apparent. Have in mind that only one basic formula is used for calculating the lines drawn along the coasts and fjords. It is the equation of the convection cell system that explains these repeated tectonic features, which remain hidden until revealed in this way.