If we just told you that this was another bonkers effect from the mind of Roddy McGhie that wouldn’t be enough. Stargate allows you to go boldly where no marker has gone before.
You put a marker through a card box. You then openly move the tip of that marker to the other end of the card box creating a visual puzzle. Then when you push and pull the marker through the card box the tip goes in and out of the hole on the other end of the card box. It’s like it’s moving through an actual portal through another dimension. This is the kind of magic that looks like trick photography in real life. You leave the holes on opposite ends of the card box, pull the market out of the box.
Here’s the crazy part. Now you can hand out the marker and the box for a thorough inspection.