Of course he knew how to swim. If he didn't he would have never jumped into the water by himself, without some kind of floating device. His punishment, twenty laps, didn't seem like a big price to pay for a moment of an amazing jump. William was just sorry he got caught, not that he had to serve the sentence. He wondered what would happen to him, should he choose to refuse swim the laps. He'd probably get dragged down to the bottom of the pool and get beaten with mermaid's tail. It was one nice theory, although he doubted that would ever happen. After all, Mrs. Andrews was here to help him, not to instill fear into his heart. Which would be a bad idea, seeing how he could shake the ground, William could do some real damage, of course if he could even control his powers.
Looking at the teacher lady, William hesitantly entered the pool again, his shorts inflating as the water got under his swim wear. He had to push it down to let all the air out, it made him look like a big dough boy. He hated that. The boy wished he had not pissed off the lady by his misunderstanding. He walked closer to deep end and then laid on his stomach as water splashed around him. Diving under, he kicked his legs as fast as he could, moving around as much as he could trying to not sink to the bottom. As air ran out, William emerged to the top and gasped deeply. Looking around once again, he realized he didn't make much of a progress. Then, to make his sentence fun, William laid on his back and began to kick his legs up and down, while moving his arms back one at the time. He was paddling on his back around the pool. Mrs. Andrews didn't say how he should be doing it, so he took the easiest way out.