The convection rolls under the tectonic plates can be represented with short sections. The most obvious example is found under the Atlantic Ocean.
These large scale convection rolls span 30` along each latitude, as shown below.
These drawings can then be used for a first step learning to be able to understand the Convection Rolls System. The convection rolls shaping the Atlantic Ocean were in fact first noticed a long time ago, but attention was mainly directed towards surface features. Alfred Wegener noticed that the continents fit together, and was clear-headed enough to see that it could be no coincidence. Then he systematically studied each side of the Atlantic, and other parts of the world, to find the global picture of tectonic drift. In the same way, we can make use of the clarity of structure of the Atlantic Ocean to understand the forces responsible for tectonic drift, volcanic activity and formation of geothermal areas.