Usually ema are small wood plaques shaped like or with pictures of animals. At Fushimi Inari they come in the form of torii gates. Worshippers write prayers or wishes on them and hang them at the shrine.
The Shinto shrine Fushimi Inari has more than 10,000 torii gates to walk through
Torii gates with lantern at the Fushimi Inari Shrine in Kyoto