An example of a human precision grip — grasping a first metacarpal from the thumb of a specimen of Australopithecus africanus that's thought to be 2 to 3 million years old.
T.L. Kivell & M. Skinner
The newly described L. larvaepartus (male, left, and female) from Indonesia's island of Sulawesi. Odd, sure, but at least they don't use their stomachs as breeding chambers, as some other frogs do.
Jim McGuire/UC Berkeley
An inside view of this fossil Pseudodon shell shows that the hole made by Homo erectus is exactly at the spot where the muscle attached to the shell. Poking at that spot would force the shell open.
Henk Caspers/Naturalis Leiden/The Netherlands
This is a re-creation of a color plate from Interaction of Color, by Josef Albers. The two X's are are exactly the same — it's the different backgrounds that make them look like very different colors.
Source: Josef Albers Interaction of Color