Custom world generation/surface rule

• •  type: Type of the surface rule, one of: bandlands [sic], block, condition, or sequence. See below of extra fields for each type.

    If  type is bandlands [sic] (used in badlands), no extra fields.

    If  type is blocks (places the specified block), extra fields are as follows:

  •  result_state: The block to use.
    • Block state

    If  type is sequence (attempts to apply surface rules in order, and only the first successful surface rule is applied), extra fields are as follows:

  •  sequence: (Required, but can be empty) List of surface rules.
    • : A surface rule.
      • Surface rule

    If  type is condition (applies surface rules if the condition is met), extra fields are as follows:

  •  if_true: A surface rule condition.
    • Surface rule condition
  •  then_run: A surface rule.
    • Surface rule