How to write a 3D image from a 3x3 matrix written in fortran 90? - image

Question

I'm trying to write a 3D image in fortran 90.
The code for the object I want in the image:
Here is a code of a cube in fortran:
PROGRAM myimage
integer xmax,ymax,zmax
parameter (xmax=10,ymax=10,zmax=10)
INTEGER mytable(1:xmax,1:ymax,1:zmax)
do 1 i1=1,xmax
do 2 i2=1,ymax
do 3 i3=1,zmax
mytable(i1,i2,i3)=0
if ((i1.ge.3).and.(i1.le.6).and.(i2.ge.3).and.(i2.le.6).and.(i3.ge.3).and.(i3.le.6)) then
mytable(i1,i2,i3)=1
endif
3 continue
2 continue
1 continue
end
The type of image I'd like to get:
The type of image I want is like this :
The cube would be my pixels mytable=1 and around it there would be pixels : mytable=0
What I tried:
I first tried to write a code to make the image directly in fortran, but it turned out that the image issued was not a 3D image as I wanted (see Appendix 1).
The question:
Could you explain me how to view that type of object in 3D please ?
For instance, following the comment of Vladimir F, I downloaded Paraview.
I found this question that is quite similar to where I stand now.
But I don't understand what exactly I have to write in the file, if I choose to write it in the format UCD. I didn't find explanations on the internet and the link that is brought in the question there does not work.
Appendix 1:
Here is a code for a 2D image and for the 3D image I tried to code.
I first wrote a 2D image that works. I tried to generalize it to 3D. I'd like to view the object where mytable=1 in 3D.
subroutine image2d(mytable,xmax,ymax,zmax)
integer xmax,ymax,zmax,mytable(1:xmax,1:ymax,1:zmax)
character*15 fname
WRITE(fname,'(a)')'myimage2d.ppm'
open (100,file=fname,form='formatted')
write(100,'(a)') 'P3'
write(100,*) '#'
write(100,*) xmax,ymax
write(100,*) 2
do 10 i10=1,xmax
do 20 i20=1,ymax
if (mytable(i10,i20,5).eq.0) then
write(100,*) '2 2 2'
else if (mytable(i10,i20,5).eq.1) then
write(100,*) '0 0 0'
end if
20 continue
10 continue
end
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
subroutine image3d(mytable,xmax,ymax,zmax)
integer xmax,ymax,zmax,mytable(1:xmax,1:ymax,1:zmax)
character*15 fname
WRITE(fname,'(a)')'myimage3d.ppm'
open (200,file=fname,form='formatted')
write(200,'(a)') 'P3'
write(200,*) '#'
write(200,*) xmax,ymax,zmax
write(200,*) 3
do 11 i10=1,xmax
do 21 i20=1,ymax
do 31 i30=1,ymax
if (mytable(i10,i20,i30).eq.0) then
write(200,*) '2 2 2'
else if (mytable(i10,i20,i30).eq.1) then
write(200,*) '0 1 2'
end if
31 continue
21 continue
11 continue
end