Tài liệu tham khảo về cách xếp hình chóp bằng giấy. | Tetrahedron Copyright 1998 Stephen Hecht. All Rights Reserved A dollar bill 66mm x 157mm produces a model 38mm on a side. 3. Swing behind. 1. Either side up. Mountain crease bisector. 2. Pivoting on A bring B to horizontal crease. Repeat symmetrically. Propagate 60-degree valley creases for a total of 8 creases. 4. Reverse-fold. Rotate 60 degrees. 5. Triangle C will be the base of the tetrahedron. All valley folds are 120-degree planar angles. Tuck D into pocket at bottom edge of C. 6. Model is now 3-D. Wrap around with 120-degree planar valley folds and tuck E into pocket on right side of front face. 7. Done. There are 2 pockets you could have tucked E into. The one in the front face covers the seam but locks loosely. The one in the right face makes a tighter lock but leaves the seam .