Polygonal Mandala - Origami Twist Fold-Decagon case

Polygonal Mandala (Decagon case)

     Fig.1-1 Outside pattern
         click to enlarge & print
     Fig.1-2 Inside pattern
         click to enlarge & print
     Fig.1-3 Resulting Mandala
         click here to enlarge
    Fig. 2-1   After Step 3-1
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     Fig. 2-2  After Step 3-2
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     Fig.2-3  After Squash Fold
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    Fig 3-1    enlarge
   Fig 3-2    enlarge
    Final Look    enlarge

The image files used here can be downloaded from the author's web site decagon mandala
(URL: http://www.takayaiwamoto.com/origami_note/eboc/eboc-2016.html)
The origami technique of twist fold, squash fold and inside reverse fold will be used.
Step 1: Print out diagrams for outer and inner pieces , then cut out the periphery.
Print out Fig 1-1 and Fig 1-2 on 8.5 X 11 inches standard printer papers.
In this example, the second paper is the green metalic origami paper cut 8.5 inches wide.
Step 2: Score the fold lines by a used up ball point pen cartridge
Score all red, blue and black lines. There are 50 lines on outside base and ,30 on the inner star.
Assuming approximately 10 seconds for one scoring action, the whole process may take around 15 minutes.
Step 3: Fold the outside base
Step 3-1:Fold the outside base following the standard folding rules. (Fig 2-1)
    (1) red line : mountain fold
    (2) blue line: valley fold
Step 3-2:Make all flaps stand up. (Fig 2-2)
Step 3-3:Apply "squash fold" to all standing flaps. (Fig 2-3)
Step 4: Fold the inside pentagon star
For clarity , both front & back side views of each step are shown .
Step 4-1:Fold the inside pentagon following the folding rules below. (Fig 3-1)
Reverse the standard folding rule.
    (1) red line : valley fold
    (2) blue line: mountain fold
Step 4-2:Apply the "Inside Reverse Fold" to 5 flaps of pentagon of Fig 3-1 (Fig 3-2)
Final Step : inserting the pentagon star on top of the decagon base
Note about "Reverse Inside Fold"
This is a common folding process often used in making star shaped polygon.
The illustration is for Reverse Inside Fold used in making 7-pointed star, but the idea is the same.
First open the closed flap section.
After making 3 lines of mountain fold, close the flap slowly
Open the closed flap section click here to enlarge hepta_string_14b-250 Inside Reverse Fold click here to enlarge hepta_string_14a-250