Thank you Ray, that's sweet of you!
(Now I notice you even went back and tested again?)
For the time being I'll use captcha :-)
I think I'll need to practice/test the goole reCaptcha anyway till I make it work so it's not going to happen soon.
Also this morning I started my iMac and edit backup-ed php file and uploaded again, and now the square thing isn't showing up. I'll keep an eye on it, and I'll come back when that happens again.