The international “don't” symbol: a circle with a diagonal line across it.
75% gray: a checkerboard pattern where three out of four bits are on.
50% gray: a checkerboard pattern where every other bit is on.
25% gray: a checkerboard pattern where one out of every four bits is on.
12.5% gray: a pattern where one-eighth of the bits are on, consisting of every fourth pixel in every other row.
An hourglass symbol.
A large letter “i”.
The silhouette of a human head, with a question mark in it.
A large question-mark.
A large exclamation point.