"I wish Karyn and I shared most of the same classes," he said. The stone flashed.
Reality changed again...in the new reality, Karyn and Jon weren't even friends. After all, she was best friends with Zoe instead.
Which meant that Jon had a different best friend, and his life had been different as a result...
Unaware of this, however, he put the stone away with an odd frown. He had to get going before he was late.