The fascinating symmetry of the convection cell system appears in this drawing:
The mountains Snæfellsjökull and Snæfell have the same distance to the division line from Ölfus, over Hveravellir and to Skjálfandi.
To emphasize further on the regularity, look at the position of Hekla:
This is one of many proofs of the existence of the system of mantle currents.