The number of health points for each shape is random within the limits set for that shape. This means that the number of health points for a red square can range from 5 to 10 HP, whilst, for example, for a circle it can range from 30 to 50.
There’s also a minor bug: if a shape’s health is less than 1 but greater than zero, the health bar will magically return to full, but this has no impact on gameplay.