I have not posted for a while, this is a busy time of year, but I thought that this might be of enough interest to post.
I will put up the image of a knot that I learned many years ago, and then an explanation and another image as a reply. You may feel that you know the knot.
Remember the old saw that perception often replaces reality until it is proven wrong.

With all the warning that I gave, you probably took a good look at the picture and saw that it was a fools knot. This picture shows that the ends and standing parts are on opposite sides. This will cause the knot to capsize and slip instead of holding. I have been told that a few bets have been won concerning slipping square knots with this one.
It is layed up like a single sheet bend without the pass under step.
It is a very simple knot but you can have a little fun with it. The slippage is more pronounced if you use a slippery line like nylon, dacron, or one of the poly- types. Natural fibers may jam in spite of the poor structure of the knot.
Have fun.