Figure 2: Four layers of the phase diagram and the transitions connecting them.
From: Multiple tipping points and optimal repairing in interacting networks

(a) Region of 11 state, in green. Possible transitions are 11→12 (orange line), 11→22 (blue line) and 11→21 (purple line). This layer of the phase diagram has two triple points, marked as black points. (b) Region of 22 state (blue), with two triple points and three transitions. (c) Region of 21 state (purple), with two transition lines (to 11 and 22 state) that merge in a critical point. (d) Region of 12 state (orange), with two transition lines (to 11 and 22 state) that merge in a critical point. (e) Illustration showing states (11, 12, 21 and 22) with allowed (blue arrows) and forbidden (red line) transitions.