Zack decided he'd try something that might be fun. First of all he reversed his wish so the room changed back to blue and his clothes changed to a baby boy's again. He guessed his current age to be about one year old. He wished for himself to age a year every thirty minutes. And then he just had to wait. He decided to find a way to entertain himself as a one year old.
He looked around his room and decided he'd go and look around the rest of the house from his small height. It was hard though, he'd only just been able to walk at a year old and so he toddled out the open door, with much falling and tripping. However when he saw the stairs and saw how steep they were, he decided against going down there until he was a little older.
His sister's door was shut, and it was now far too high for him to open. Then something came up that was a real problem: he had to use the washroom. He had a diaper on sure, but he didn't want to go in that. He still had a teenager's mind and that was gross. "Aw has ta wat," he burbled, having immense difficulty with that single sentence.
He tried to hold it in, not easy with his smaller bladder. He stumbled into his parent's room and saw the digital clock read 8:25. He'd made the aging wish at 8:00, so he only had five minutes to go before he aged. He plopped onto the ground and tried as hard as he could to hold it in. Meanwhile he studied his small, pudgy arms without any muscle at all. His small body, with baby fat and his hair that was still growing, and a very light blond.
Zack looked up at the clock and saw it change to 8:30 and right on cue he began to grow. He got taller, his hair became thicker, and his baby fat vanished a little. What he noted mostly though was that his legs strengthened. Now he could actually walk. He also noted how the shirt was shorter and the diaper had become awkward. A second later he was wearing a larger t-shirt and a pair of soft pyjama pants.
The two-year old grinned showing his new teeth and got up, enjoying his slightly better walking ability. He moved as fast as he could to the washroom, the door was open luckily cause he still wasn't quite tall enough to reach the knob. He managed to relieve himself of the pressure in his bladder, which had actually lessened with the growth spurt cause he now had a bigger bladder.
Zack once again returned to the stairs, but still was unsure about tackling them. Instead the young boy returned to his room to find it hadn't really changed. The crib's walls were a little lower and there was a number of stuffed animals in the room, as well as fewer babyish objects. He found some large Duplo blocks and started just building random things to try and entertain himself. While he did have a teenager's mind, there was some slight changes in that he enjoyed playing with childish things.
He somehow managed to get so distracted he took a moment to realize that he was growing again. His clothes grew larger with him, after a brief moment of uncomfortable tightness. But most importantly, he could walk much better than before. His hair was longer as well. He decided once again to try the stairs, after watching his room morph a little more, once again losing some more babyish items, and with newer items coming in.
He did this time make it down the stairs and marvelled around at how much bigger the house was from his small height. "I know!" he cried suddenly, an idea hitting him. He made a wish and a moment later another boy who looked almost exactly like him came down the stairs. Zack was now a twin.