36 new icons:
square-rounded-letter-a
square-rounded-letter-b
square-rounded-letter-c
square-rounded-letter-d
square-rounded-letter-e
square-rounded-letter-f
square-rounded-letter-g
square-rounded-letter-h
square-rounded-letter-i
square-rounded-letter-j
square-rounded-letter-k
square-rounded-letter-l
square-rounded-letter-m
square-rounded-letter-n
square-rounded-letter-o
square-rounded-letter-p
square-rounded-letter-q
square-rounded-letter-r
square-rounded-letter-s
square-rounded-letter-t
square-rounded-letter-u
square-rounded-letter-v
square-rounded-letter-w
square-rounded-letter-x
square-rounded-letter-y
square-rounded-letter-z
square-rounded-number-0
square-rounded-number-1
square-rounded-number-2
square-rounded-number-3
square-rounded-number-4
square-rounded-number-5
square-rounded-number-6
square-rounded-number-7
square-rounded-number-8
square-rounded-number-9