You have no idea how excited I am that you asked this.
Build a stepped castle wall. The bottom most level of wall is X wide, the next going up is X-1, then X-2, X-3, etc. The upper most wall section is one wall thick, so this is probably where you want to put widows, archery loops, etc.
In the schematic (attached),
Grey=3Ø 24 763Ø (or like)
White=3Ø 24 763Ø (or like)
Blue=3Ø 21 158Ø
The lower sections at at least 2-wide, so you may want to brace them every so often (such as 30 26 1040), and you may or may not want to put 3Ø 24 763Ø’s at the base (better footing). Something to consider.