Goofing with QR Codes

I've created a QR code for SaltwaterWitch.com (black and white) that works just like it's supposed to, but I started playing around with colors and how far I could distort the code and still have it readable.  I got pretty far.  If you have a QR code reader on your phone let me know if any of these don't work. They all worked with mine, although I had a bit of trouble with the last one.  I suspect I'm getting to the edge of what's readable.