This one has two twists instead of the normal one, and comes out like a square knot if done right. It won't come untied by itself, ever. But you can untie it by tugging on the tails of the laces. You can do this one with a thumb on the initial bend, unlike the "bunny ears" style knots.
It's a hell of a lot better than the "double knot" your kids' teachers will do if they go to school with any kind of single knot, square or not. Double knotting just results in big jams when one tries to untie it later.
Check out the surgeon's knot: https://www.fieggen.com/shoelace/surgeonknot.htm
Is it the security/convenience ratio?
security=1/convenience
EDIT: Wait! I didn't notice this:
"Now, simply pull the loops to tighten the knot. The whole twisted mess of the previous drawing will rearrange itself into exactly the same finished knot as my Ian's Secure Shoelace Knot."