Pi is an irrational number (meaning the digits never end or have a repeating pattern) that is the ratio of the circumference of a circle to its diameter...this ratio is a constant for any circle, regardless of size.
The universal recycling symbol (U+2672 â² universal recycling symbol or U+267B â» black universal recycling symbol in Unicode) is an internationally recognized symbol used to designate recyclable materials.It is composed of three mutually chasing arrows that form a Moebius mÃ¶bius (strip an unending-single sided looped). surfacehe recycling symbol is in the public domain, and is not a trademark. The Container Corporation of America originally applied for a trademark on the design, but the application was challenged, and the corporation decided to abandon the claim. As such, anyone may use or modify the recycling symbol, royalty-free.
The Recycling Symbols. 1  Plastic #1 â PETE or PET (Polyethylene Terephthalate) 2  Plastic #2 â HDPE (High Density Polyethylene) 3  Plastic #3 â V or PVC (Vinyl) 4  Plastic #4 â LDPE (Low Density Polyethylene) 5  Plastic #5 â PP (Polypropylene) 6  Plastic #6 â PS (Polystyrene) 7  Plastic #7 â Other, Miscellaneous.