My favorite tetrapod pics:
http://jpatokal.iki.fi/photo/travel/...t_ShakeHip.JPG
http://jpatokal.iki.fi/photo/travel/..._Port_Jump.JPG
Incidentally, if you follow the instructions, it's about 70 km to Taipei.
...and, to bring this vaguely back on topic, Miyajima doesn't seem to have any of the spiky things. Another worthwhile excursion from/on the way to Hiroshima is
Okayama, which has a rather striking castle and famous but rather bland garden right next to it. To get even more off the beaten path, drop into
Onomichi, where you can take the "Path of Literature" past dozens of temples scattered about a hillside.