Bladeless Butterfly Knife Fidget Toy

How it works: Each handle has a forked pivot end, and the link sits inside the fork. The back wall of the fork stops the handle, so it locks flat in both the closed and open positions. The handles swing outward and flip just like a real balisong. I checked that the parts don't collide when closed, mid-flip, and open.

• Print the handles flat. Turn on supports, because the fork slot at each pivot end needs a small support area. Tree supports come out easily since the slot is open on three sides.

• Use PLA or PETG, 3+ walls, and 20–30% infill. Print the pins standing up.

• The pin holes in the handles are 3.1 mm so the 3 mm pins press in snug. The link holes are 3.6 mm so the link spins freely.

• To assemble, slide the link into both forks and press a pin through each pivot. You can also use 3×10 mm steel dowel pins, which make it more durable and a little heavier.

• Stealth Slots has two long rounded windows in each handle and squared-off tips. It's the lightest of the three and looks clean and tactical. It would look great in black or gray.

• Honeycomb has a row of 8 hexagon cutouts and fully rounded tips at both ends. It has a techy, sci-fi look and suits bright colors like yellow or orange.

• Speed Holes has 7 round holes that shrink from the pivot toward the tip. It has a racing or sporty feel and is the heaviest of the three, so it flips with more momentum.