The only thing that Bill Gates created
Was MS-Basic
And he did that by taking a listing of the assembly language code of a PDP-11 Basic interpreter
From Harvard computing center
And translating that to 8080 assembly language
A bit of work, but not really that hard to do
Any 3rd year comp sci student in the late 70s
Should have been able to do this.
He had helpers and advisors for everything else that he supposedly did.