Use 30 rectangle (A ratio) sheets of A4 paper.
Difficulty : ⭐⭐⭐
Time: 2 hours
 
Ruby Unit designed by Nick Robinson. 
 
Model paper size: 
Unit (brown) : 5.25 cm x 7.4 cm (divide A4 to 8 pieces)
 
Model height: ~ 12 cm
 
PrwOrigami - Kusudama Collection
www.prworigami.com
(October, 2019)