14, 11 bytes
3 bytes saved thanks to @nmjmcman!
00000000: c4f2f26c 4778d978 6c5848c4 6bd92478 78483e3e c424ea 783e . .GxlXkl.xH.$x>$x>>.
Original approach (18 bytes):
ò " Recursively: l " Move one char to the right (this will break the loop if we move too far Ù " Duplicate this line down x " Delete the first character on this line H " Move to the first line Ä " Duplicate this line up $ " Move to the end of this line x " And delete a character >> " Put one space at the beginning of this line ê " And move to this column on the last line " (implicit) ò, end the loop.