This is one of the illustrations for the book - investigating the formation of rifting geology (where plates split and form new continents or valleys). The idea is to let the student look at the image and try to figure out what's going on... a sort of visual test. While these images appear simple to begin with, they hold a wealth of information like the basalt (lava) flows at the top right of the large rift. This tells students of the deep nature of this kind of a rift - deep enough that lava pushes up and out in a huge area. Anyway - this is another 4 to 5 hour piece. zBrush, Lightwave and Photoshop. (And Illustrator for line work) were used to make this one.