Need to get your strategies into something you can see? Lines let you do just that. Right clicking and dragging draws a line that follows your cursor around. Right clicking again places the line. The lines are automatically centred so that they snap to the centre of the squares. If you line starts and ends at the same place it creates a circle instead. I also spent lots of time making sure my bitboards are used properly as when I created the array last time I used it for more than I intended and lost most of the arrays of bitboards. I also noticed that the promotion GUI wasn’t properly centred and so fixed that. I don’t really like the lines as they use stipples instead of a solid colour and overall don’t look nice but tkinter doesn’t offer transparency apart from stipples and doesn’t allow lots of customisation of the arrows. Next I will likely try to add en passant.