My imagination, I guess. I was not even aware of the existence of any Star Trek toys at the time. I would set up folding chairs in the garage to look like the bridge. The helm was a long table with two chairs behind it, and the viewscreen was a chalkboard! Me and a friend would play Star Trek like that. Then we'd "Beam down" by walking out the door to an "alien planet" (The backyard.) and have adventures! We made up a pretty elaborate Star Trek board game once, too. Big poster board with dice, game pieces and squares telling you what to do when you landed on them, cards like monopoly, all that stuff. Fun times!