Recursion: Underscore-Hash Staircase

Create a function that will build a staircase using the underscore _ and hash # symbols. A positive value denotes the staircase's upward direction and downwards for a negative value.

Examples

staircase(3) ➞ "__#\n_##\n###"
__#
_##
###

staircase(7) ➞ "______#\n_____##\n____###\n___####\n__#####\n_######\n#######"
______#
_____##
____###
___####
__#####
_######
#######

staircase(2) ➞ "_#\n##"
_#
##

staircase(-8) ➞ "########\n_#######\n__######\n___#####\n____####\n_____###\n______##\n_______#"
########
_#######
__######
___#####
____####
_____###
______##
_______#

Notes

• All inputs are either positive or negative values.
• The string to be returned should be adjoined with the newline character \n.
• You're expected to solve this challenge using a recursive approach.
• A non-recursive version of this challenge can be found here.