Since human depth perception relies on calculating the difference between the angle of view coming to each eye, the result is a 3-D optical illusion.

FORBES: Adventures in the Third Dimension

The most striking difference between the LPGA Tour now and 10 years ago is the depth of talent.

WSJ: The Comeback of the LPGA and Women's Golf | Golf Journal by John Paul Newport

The former Leicester, Brive and Sharks number 10 says the big difference between Worcester and their play-off rivals is the strength in depth, funded by owner Cecil Duckworth.

BBC: Worcester Warriors must win promotion - Andy Goode