
      dimension x(100,100),y(100,100),z(100,100)
      
      it=36+1
      jt=18+1
      dit=3.141592*2.0/(it-1)
      djt=3.141592*2.0/(jt-1)
      
      r0=10.0
      r1=50.0
      
      do 10 i=1,it
      do 10 j=1,jt
      x0=r0*cos((j-1)*djt)
      y0=r0*sin((j-1)*djt)
      x(i,j)=(x0+r1)*cos((i-1)*dit)
      z(i,j)=(x0+r1)*sin((i-1)*dit)
      y(i,j)=y0
   10 continue
      
      open(99,file="donuts.dat")
      write(99,*) 2
      write(99,*) it,jt
      do 20 i=1,it
      do 20 j=1,jt
      write(99,*) x(i,j),y(i,j),z(i,j),0.0
   20 continue
   
      write(99,*)
      write(99,*) it,jt
      do 30 i=1,it
      do 30 j=1,jt
      write(99,*) x(i,j)+r1,z(i,j),y(i,j),0.0
   30 continue
      stop
      end
      
      
      