Zabadab

alias /shifty {
  if ($1 == $null || $1 !isnum 1-15) {
    return
  }
  var %i = 1
  if ($2 != $null && $3 != $null) {
    while (%i != $1) {
      say $2
      say $3
      inc %i
    }
  }
  else {
    while (%i != $1) {
      say <_<
      say >_>
      inc %i
    }
  }
}