I used to spend hours and hours doing knot and rope work. I've been doing less since I've been spending so much time writing and editing. But tomorrow my service dog Molly and I head off to the US on a family visit. On our last trip in March, we had trouble coming home, because I had to remove everything with metal from Molly, which meant her vest, her collar, her harness, and her leash, and send them through the x-ray machine to get through security. Then Molly, who was at this point naked had to sit and stay an appropriate distance from the metal detector until I was through and approved. Molly handled it like the pro she is, but I found it a horribly stressful experience. I had visions of people stepping on her tail or banging into her or doing something else to freak her out. And even worse that security itself was getting my stuff and hers out of the machine to put it back on her and keep it all safe. I don't do well with stress.
So for this trip I made a new collar-leash combo completely out of rope and parachute cord.
At first glance, it looks like a choke collar, but Molly neither needs nor does well on a true choke. With the stop knot I tied, the collar can tighten to almost snug.
The knot on the eye loop slides, so I can snug it down in use and loosen it if i need to get the loop past the smaller stop knot to make it easier to remove.
The reason it looks like a collar on both ends? To make the handle for me comfortable (I can always tie a bowline loop in between to short the leash to the desired length... it is pretty long for walking because of the security situation). Also it means I don't have to stress about which end is which, since they're the same. And we could in theory use it in other situations with a dog on each end.
These knots are actually relatively simple for me, although the ring knots are a bit complicated. But I do a number of other turks head and pineapple knots also.
Oh, forgot to mention. The gold rope is 6mm marine grade (leftovers from rope halters) and the parachute cord is 4mm. The rope is doubled in the collar and handle sections to make it wider and more comfortable.