this is the first instructable on how to make an origami flip knife, which of coarse can flip in and out.it is fairly simple and only needs a square sheet of paper, but entertains for hours.

Step 1: Starting Folds

start with colored side up, and fold diagonally from the upper right corner to lower left, and the upper left corner to the lower right and unfold

Step 2: 'kite' Fold

fold the lower left hand corner to the middle, using the middle line as a guide and do the same on the right side.

Step 3: Fold

fold corners that were folded in on the last step to the lines.

Step 4: Fold More

prefold both ends to the triangles, unfold, and flip the model over. now refold in the opposite direction like in picture 3.

Step 5: Fold Even More...

now fold the far end to the middle,like picture 1, and fold the bottom up to the line like picture 2. nowww, fold the close side to the middle, and it should look like the last picture.

Step 6: More Folds......

fold the tip down a little as picture 1, and then fold the little sides down like #2, and fold in half.

Step 7: Almost..

fold the white part diagonally each way like pictures 2+3, and push on each side so it looks like picture 4.

Step 8: Too Many Steps

push the white part down and away from you, and bring the other side in the same.

Step 9: Lock the End And.. You're Finished!

go to the other end and partly open it.look at the left flap and put the right flap in it.now you're D-O-N-E!!!!
to open knife, hold the tip inside the handle and pull up like a flip blade.