I've lived in Toronto for just over a year now. I take the TTC almost every day. I've always loved the little Keep Arm In signs in the streetcars, and there's even an interesting article on Torontoist about them.
My first mission was to create a one-of-a-kind necklace (first 4 photos) by acquiring one of the actual plaques from the streetcars. I got lucky and got one through a friend who works at the TTC - although it has an upgraded font, it's still authentic. I can't wait to wear it at a local event.
My second mission was to create a some-of-a-kind necklace based on the sign for people to buy. It's much smaller and vintage style, made from metal. Currently, you can buy them from here or my website for $10.