The process of stacking ingots is as follows:
0 1
Fold from bottom to top, leaving about one centimeter at the top.
02
Turn around and fold the short side up, still one centimeter higher than the first fold line.
03
The lower paper is folded, and the edge is aligned with the first folding line.
04
The two sides are folded inward into a triangle.
05
The extra centimeter refracts downward.
06
Put your thumb in the folded groove and gently push the concave part on both sides with your index finger. Many times, the ingot will bulge. If it is not ideal, then hold the upturned parts on both sides and gently pull them out to make the middle bulge and slightly reshape. Take a picture, so this is a one-handed posture.
07
After folding, there should be a neat ridge in the middle.