This is a new version on an old puzzle. Invented by Sam Loyd 1841-1911. The puzzle is placed on a buttonhole and seems impossible to remove. This is where the term buttonholed (to get someone's attention) came from.

Step 1: Materials and Tools

You will need strong string and a piece of pipe.
I used para cord and some copper pipe 1/4 O.D. x 5/32 I.D.
The main thing is to pick something small enough to fit thru a buttonhole.
Tools:
Something to cut the para cord. A hot knife would work best, I used the knife on the Multi-tool.
Something to fuse the ends of the para cord. I used a lighter and a candle.
Something to cut the pipe. A pipe cutter or hacksaw. I used the saw on the Multi-tool.
Something to smooth the pipe, after cutting. I used the file on the Mulit-tool and fine sandpaper.
Something to crimp (Smash) the pipe. Pliers, hammer, press, clamp whatever, not your teeth.

Step 2: Cut the Pipe

You will need to cut the pipe 2 inches long. If you get your pipe from the local plumbing supply store, tell them you need a few two inch long pieces of 1/4 inch pipe. They will think you are crazy and probably not charge you for it. Remember to make an extra puzzle to give to the guy at the plumbing store, even if he does charge you. Karma is something that goes around and good karma travels faster.

Step 3: Smooth Edges of Pipe

Smooth the outside and inside edges of the pipe. Use a file followed by sandpaper. If you role the sandpaper into a cone shape it gets the inside nicely. Note in the pictures that the puzzles are assembled, you should smooth both ends before assembling the puzzle, I just forgot to take pictures till after wards.

Step 4: Cut Para Cord

Cut the para cord to 5 inches long. I like to use a lit candle to cut and seal the cord at the same time. You could even cut the cord with another cord https://www.instructables.com/id/Cutting-cord-without-a-knife/ whatever works for you.

Step 5: Don't Let the Ends Fray!

Whenever you cut rope, twine, or cord, seal the ends. It will keep it from fraying and is especially helpful in the next step of the puzzle.

Step 6: Insert the Para Cord

Insert both ends of the para cord into one end of the pipe. You want the ends of the cord to go into the pipe 1/2 an inch. This is usually easiest to insert one end in a little, and then stuff the other end in. It will be a tight fit. Make sure the loop "bight" of the para cord is not long enough to go over the other end of the pipe, that is what most people will try and do to remove the puzzle from the buttonhole. Note pictures show pipe crimped, once again getting ahead of myself.

Step 7: Crimp the Pipe

Crimp the end of the pipe. The crimp should flatten out the first 1/4 to 3/8 of and inch of the pipe. This will hold the ends of the para cord inside the pipe. To keep the pipe smooth it is best to use pliers or a vice without teeth or a smooth cover for the teeth.

Step 8: Admire Your Work

If you make one or one hundred, now is the time to admire them in all their simplistic glory.

Step 9: How to Implement the Buttonhole Puzzle.

Make sure you know how to put on and remove the Buttonhole Puzzle BEFORE trying it on someone. Find someone in a shirt with buttons. Make sure that they want to try the puzzle. Warn them that they could be driven insane. Let them inspect the puzzle. Explain that you will place the puzzle on their buttonhole and that they will try and remove the puzzle without cutting the cord, or their shirt.

Step 10: Unbutton One Button

Unbutton one button. Midway down the shirt works best.

Step 11: Load the Puzzle

Feed the buttonhole and surrounding fabric thru the para cord loop of the Buttonhole puzzle. Pull enough thru to insert the opposite end of the pipe into the buttonhole. To make the puzzle more difficult, ask the victim to not watch this step.

Step 12: Smooth Out the Puzzle and Enjoy.

Smooth out the puzzle and the shirt and observe the struggle. Some people will give up quickly, others will insist on "a few more minutes". Some people will figure it out. Ones that do not figure it out will think they get it, when they watch you take it off. Ask if they want to try again. Be careful some people can get very upset. Chose your subjects wisely.