( tbl$(mytable,100)
& 5:?(30$mytable)
& 9:?(31$mytable)
& out$(!(30$mytable))
& out$(!(-169$mytable))      { -169 mod 100 == 31 }
& out$!mytable               { still index 31 }
& tbl$(mytable,0)
& (!mytable & out$"mytable still exists"
  | out$"mytable is gone"
  )
);