Recycling symbols

Many of us wonder what do these symbols mean.

The Plastic Bottle Material Code System was designed to be easy to read at a glance and distinguishable from any other marking on the bottom of a plastic container. The symbol consists of a triangle formed by three "chasing arrows", with a specific number in the center that indicates the plastic resin from which the bottle is made.

Unfortunately, the presence of one of these symbols doesn't mean that these materials may be recycled everywhere....