Fold the paper in half upwards to make a triangle.
Fold the top corner down so that the edges meet, and unfold after making a line.
Fold the corner up so its tip meets the edge of the paper at the line you made. Next, fold the other tip up so it meets the corner you just created.
Fold the top flap down toward you. Fold the other flap down to the back side of the figure.
Open the top and you have a cup ready to hold water!