Abstract
Researchs about mosaics consisting of regeular n-gon as a unit-tile have finished from n=3 to n=7,next is n=9. A whole number 9 is an odd having a prime 3 as a divisor. Bat from geometricat view-point, it means regular 9-gon involves regular triangles. In this sense, if same shapes suggest some other shapes, we call then "hiddemshapes" This is a research of regular 9-gon and hiden shape.
