Sonic Channel staff on their blog:
It is Silver wishing upon the tanzaku with the decorated bamboo in hand at the night of Tanabata.
This time, above half the people gave the right answers for the decorations tanzaku and bamboo. And there seemed to be many answers that captured Silver’s personalities like “wishing for peace” from his strong sense of justice. I hope that Silver’s wishes of being stronger than anyone and of the happiness of the peaceful days will come true.