Hey, that's a great question! They are meant to be white box on a gray background, but they're not showing up in the PDF for some reason. I'll see about getting the file updated. In the meantime, to clear up the confusion: Heat maxes out at 4, and Revelations max out at 3. The last box is (supposed) to look different because they trigger special moves.
Have fun! I'd love to hear how it goes!