2D becomes 3D
/Spotted by Guy, here is a really interesting (and useful) application of a 3D optical illusion as opposed to merely aiming to please the eye (and the mind). The illusion itself has been used to perform the function of appearing as a zebra crossing (which it is); but also through its illusory nature, serving to actively slow approaching drivers down (perhaps more importantly).
Have a look at more coverage here.
Thanks, as ever, to parentheses (you know who you are).