Since the person I bought them from was selling two, we put one inside and one outside.
True to Jasper form, he climbs up the slide with a car or truck in hand, then turns around and slides down. He even climbs up with his sippy cup in tow. He ALWAYS has to have something in his hand. It's not easy for him to climb up the slide, let alone with only 1 free hand.
Jasper loves a good obstacle!