I would like to advise your readers of an effective technique for training your human. I myself am an extremely sensitive creature with a low tolerance for noise and change of any sort. Despite being aware of my character, my human sometimes insists on changing my litter tray for one of a different colour or even changing the brand of cat litter. As other sensitive souls will know, these kinds of changes can play havoc with your enjoyment and relaxation when using the bathroom facilities.
In order to alert my human to the serious nature of her misconduct I have developed the protest poo. It involves merely pooing, quite deliberately, on the front doormat. This has the advantage of being an unmissable message and it is distinguished from other "accidents" by its regular position. I've found that after just one protest poo my human is now alerted to my displeasure and she immediately changes the litter tray and litter back to my preferred combination.
We too have taken up prtest pooing. Our humans recently informed us that our favorite litter, Beauticats clumping wood based litter, couldn't be found anymore. So we've taken up protest pooing with a vengence! If anyone knows where this cat litter can be found our humans would really like to know!