It started as a guerrilla street art project in Cambridge aimed at beginning a conversation. Then it quickly became something else, a grass-roots movement that spread quickly, because it requires no language and no explaining. You just have to consider two very similar images.
One image is the wheelchair symbol, which has become one of the most familiar icons in the world since it was introduced in 1968. The other is an edited version, with the human distinct from the chair, in an active position, with a feeling of forward movement.