I have a bookcase in which the different 'bins' are different themes (e.g. history, computing, crafts, non-fiction, etc). I now have a sudden compulsion to arra

I have a bookcase in which the different 'bins' are different themes (e.g. history, computing, crafts, non-fiction, etc). I now have a sudden compulsion to arrange the books in each by colour to see what it looks like.