I am aware of the invisible pieces in the theme section to practice blindfold chess, but I would like to suggest some new sets of pieces to be able to practice «semi-blindfold». There are in fact three levels of semi-blindfold: 1) Normal pieces but all are grey, so you don't see which ones are your own and which ones belong to the opponent. 2) All pieces look like checkers pieces (completely similar), but you can see which ones are black and which ones are white. 3) A combination of 1 and 2 - grey checker pieces, so you still see where there are pieces on the board, but you don't know whose it is and you don't know what kind it is. Would it be possible to create sets of pieces that allow for these different training modes?