anchor.diff:    s_rot  = s
     xp_rot = xp
   
  -  s_shift  =  s_rot*c_cnTilt+x_rot*c_snTilt
  -  x_shift  = -s_rot*c_snTilt+x_rot*c_cnTilt
  +  s_shift  =  s_rot*c_cnTilt + x_rot*c_snTilt
  +  x_shift  = -s_rot*c_snTilt + x_rot*c_cnTilt
     xp_shift = xp_rot + cry_tilt
   
     ! 2nd: shift back the reference frame
  
positive.code:   use mathlib_bouncer
    use physical_constants
  
    integer,          intent(in)    :: is
    real(kind=fPrec), intent(inout) :: x
    real(kind=fPrec), intent(inout) :: xp
    real(kind=fPrec), intent(inout) :: y
    real(kind=fPrec), intent(inout) :: yp
    real(kind=fPrec), intent(inout) :: pc
    real(kind=fPrec), intent(in)    :: length
    integer,          intent(in)    :: j
  
    integer nam,zn                        ! Switch on/off the nuclear interaction (NAM) and the MCS (ZN)
    real(kind=fPrec) ymax,ymin            ! Crystal geometrical parameters
  
negative.code: ! ================================================================================================ !
  !  Subroutine for the movements of the particles in the crystal
  !  Simple tranport protons in crystal 2
  ! ================================================================================================ !
  subroutine cryst(is,x,xp,y,yp,pc,length)
  
    use mod_ranlux
    use mod_funlux
  