Guy from Burn Notice
Toph Bei Fong
These are just what I can think of right now who have been guessed as both types. Why (prefferably functionwise) is this?
I mean, they're not THAT similar. How can one determine which is correct when they're so easy to confuse?
And another thing. Is common for ISTPs to invent things and develop complex plans? Because that seems rather N, but I hear they do.