Follow the steps below to learn how to make an origami sink fold.
This origami sink fold example begins with a waterbomb base, which is a triangle with four flaps. What is a sink fold? It's purpose is to "cut off" or "sink in" a pointy part of the origami.
|Step 1: Starting with a waterbomb base, fold the tip of the triangle and unfold.
|Step 2: Open up the triangle.
|Step 3: Here's where you'll need to perform some origami-fu on the paper to make the sink fold work. Flatten the top so that the whole piece resembles a table, then manipulate the creased sides of the triangle so they can come to the center while sinking in the point at the same time.