Entropy along isotherms of revised AQUA (top row) and original AQUA (bottom row). The low-T panels (left) show isotherms passing through regions 1, 2, and 3, or through 4, 7, 3 (+ extrapolations of region 3). The mid-T panels (center) show isotherms passing through regions 6, 7, 5, and 7 again. The high-T panels (right) show isotherms crossing regions 6,5 and 7 or just regions 6 to 7 for the highest temperatures. The low-T panel for the original AQUA shows a kink around 1.83 · 10¹⁰ Pa for several isotherms around 800 K, and a sudden rise in entropy at 3 · 10¹¹ Pa. Both features have intentionally been removed in the revised AQUA. The numbers on panels a, c, and e indicate the regions of the phase diagram as shown in Fig. 1 crossed by the isotherms.