Why are European recycling codes so complicated? [on hold]

Each time I recycle my garbage, I must wonder why are these European recycling symbols so complicated. For example this one:

This symbol is really cryptic for me as a user. PP could stand for both "paper" and "plastic" and 05 provides no information at all without a code table in my head.

What I really need to know is which of these I should use:

I find it really frustrating.

How could we improve recycling symbols on our products to make them self-explanatory, high-contrast enough on all type of packages of different colors and providing useful information for users?