Note that a “valley fold” refers to a type of origami fold in which you fold the edge in your hand in, toward you, rather than folding it out and away from you.

For this step, you should only crease the center of this fold and not the entire length. The center of your creased portion should intersect with the first pre-crease you created in an earlier step. When done, turn the paper over so that the inside side faces you.

When done, flip the paper over so that the original side shows again.

Turn the paper over to the other side again.

You will be left with what looks like a diamond with tall upper half and a short lower half.

More precisely, look at the rectangular portion lying behind the diamond shape. This section needs to be folded in half as you fold up the bottom tip. When done, turn the paper over again.

When done, turn the paper back over.

A mountain fold refers to a fold made in which you fold the edges outward, creating a “mountain” peak facing you. When you pleat in origami, you use both a valley fold and a mountain fold. Make the valley fold to the inside of the intended mountain fold. Then, mountain fold the edge back along the instructed point. When done, turn the paper over.

Rotate the model until the largest triangle, which forms the tail, can rest on the table. This step completes your origami T-Rex.

A valley fold is a type of origami fold in which the edge you work with is folded inward toward you, creating a “valley” or depression along the fold. At the completion of this step, rotate the paper by 45 degrees. It should now be in a diamond position, with one corner at the top and another at the bottom.

When done, turn the model over to its other side.

Note that your bottom edge will meet the pre-crease made immediately prior to this.

For your second pre-crease, repeat this same procedure with the left side of the triangular section.

Note that the bottom edge of each crease in this step should stop at the lowest visible diagonal pre-crease made previously.

Note the distinguishable downward pointing triangle at the bottom of the model. Valley fold this piece in half vertically. Mountain fold the top part of the model in half vertically. Valley fold the top two diagonal pre-creases and the bottom two diagonal creases. Example the remaining pre-creases, which were made from your first set of pre-creases. Valley fold the inner portion of both creases, stopping when you hit other creases. Mountain fold the rest of these two pre-creases. When done, turn the model over.

At this point, you should compress the model by taking the triangular side flaps and pinching them in. Rotate the model by 90 degrees before continuing further.

Note that the true lower corner of this flap lies beneath the visible surface of the model. You will need to use this corner and not the visible corner when folding.

When done, rotate the model by 90 degrees.

Turn the model over to its other side when done.

When done, rotate the model by another 90 degrees. You should be able to distinguish two clear wing portions and a body portion. Spread the wings apart by gently pushing them down and away from the body.

Note that the newly created flat region should look triangular in shape. Turn the model over when done.

After this, you will need to make another more dramatic set of curved valley folds. These folds should connect the outer-most corners of either wing to the innermost bottom corners of each wing. The curve should go inward at a gently angle. After making your curves, tuck the lower flaps produced by those folds into the upper flaps lying underneath. Turn the model over when done and rotate it by 90 degrees.

The head should be on the right side of the model. When done, rotate the model again by another 90 degrees.

The head should be on the right during this step. Turn the model over when done. Repeat this same procedure on the head from the other side, and rotate the model until the wings are spread out flat in front of you and the head faces toward the top.

This step completes the model. Examine it from all sides and redefine any creases that appear loose, if desired, to strengthen the overall shape.