Python 3, 59 bytes
lambda l:[' '*i+'%c '%(i+65)*-~i for i in range(ord(l)-64)]
Python 3, 61 bytes
lambda l:[' '*i+-~i*(chr(i+65)+' ')for i in range(ord(l)-64)]
Try it online! (link to pretty-print version)
Mr. Xcoder
- 42.9k
- 9
- 87
- 221