The mysterious symbol turned up multiple times in this episode:
1. On the cover of Chandra Suresh's book.
2. On the side of Claire's math book.
3. On the picture of Nathan on Sylar's map.
4. Within Chandra's program as a repeating gap making the symbol.
5. In the pool using floating toys.
6. On the necklace of the man in the bar, whose thoughts can't be read by Matt.
7. On the cover of the comic book Hiro has, drawn by Isaac.