STATIC variable [, variables]
Defines a list of variable names which are local to the subroutine or function.
These variables will retain their value between calls to the subroutine or function (unlike variables created using the LOCAL command).
This command uses exactly the same syntax as DIM. The only difference is
that the length of the variable name created by STATIC and the length of the
subroutine or function name added together cannot exceed 31 characters.
Static variables can be initialised to a value. This initialisation will take effect only on the first call to the subroutine (not on subsequent calls).