initialFENState property
Adjust the initial state FEN so that the first rank (board.0) corresponds
to the first row in the FEN and the last rank (board.7) corresponds to the last row.
For example, if you want white pieces at the bottom (board.0), then your FEN might look like:
'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w'
Implementation
String initialFENState =
'rnbqkbnr/pppppppp/8/8/8/8/PPPPPPPP/RNBQKBNR w KQkq - 0 1';