Earth regions

The earth has several regions, each divided into areas which contain 10 layers. The last layer in each area has more health points (HP) than the first nine layers in that area. At the end of area 5, 10, 15, and 20 in each region is an obsidian layer. At the end of area 25 in each region is 3 obsidian layers.

"Normal layer" health (Area 1 to 9 of each region) follows the following function:

$${hp = 50 \times (\frac{6}{5})^{area number - 1}}$$

Area 10 has 5 times as much hp as normal layers.