Icons are used widely to provide information in a small area and, the argument goes, easily recognisable form. At this "bring and show" session you are encouraged to come along with an icon you think is particularly useful or smart in design and (the easy bit) one you find wonderfully bad.
As a starter for 10, the following three icons are legal UK road signs. The first is the maximum speed (high legibility at a distance but should it say MPH?), the second maximum weight (in tons) but what on earth is the third?
PS: Don't mail me - I know what it means...