Comparing the west coast of Greenland with Iceland at the same latitudes reveals a common point. At 66°N the coasts are exactly 30° apart. As mentioned before, the basic extension along each latitude is 30°, because each convection roll is 30° wide.
Besides that, similar consistency is found between tectonics and analysis of convection rolls of the mantle in both countries.
This is how it looks:
Just to have Iceland in similar scale to make comparison easier:
There you see that the fjords of NW Iceland follow the equator originated set of lines to the NW, but in Greenland to the NE, but the deviation from east is actually the same, that is 35°.