Jeff decided to pick one of the more simple presets. He didn't want to attempt writing something out from pure scratch. He'd probably mess it up somehow. But he knew that he did not want this new pocket dimension to be in his bedroom. He did need to sleep after all.
He selected the college campus gym preset, which opened many different subsets. He could expand them to understand the new reality completely, but he wasn't really interested in that. He picked one of the subsets at random. He set the entrance to the gym to be the bathroom door right next to his bedroom. He set it up so that he would change to match the surroundings but would still keep his memories of this reality. That way he could still have fun without seeming too out of place. He also set it so that it would only work if Jeff himself opened the door, and anyone else who went through the door with him would also change to blend in but be unaware of it.
He double-checked his work and pressed enter. The screen showed a loading bar for a few seconds before the program dinged. The change was complete.
In less than 30 seconds? And not even his bedroom wall shook?
Jeff took a nervous breath and shut off the monitor. He didn't want his family snooping in his room. He left his bedroom and stared at the white bathroom door. It was closed, which it only ever was if someone was inside. He took another breath and grabbed the doorknob.
The moment his hand touched the knob, it warped into a metallic handle. The rest of the door changed into a simple wooden, unpainted door with stainless steel trimming. He turned the handle and pushed.
On the other side was not his bathroom. It was a huge and bright room with tons of windows from the top of the three-story size ceiling down to the floor. Jeff glanced at the ceiling above him, nowhere near as tall as what was on the other side of the door. He could hear voices coming through the doorway as well. He nervously stepped through and closed the door behind him. It was completely blank, like what one would expect a janitor's closet to look like.
He gazed up and saw a spiraling staircase next to some basketball courts. It led up to two more floors that he could tell had various workout equipment sprawled out. He heard some music playing on a speaker system, too. He was just about to explore this place when he felt a tingle flow over his body. He almost forgot that he would change now that he was here.