Shifty Eyes is an esoteric language inspired by this comment: http://codegolf.stackexchange.com/questions/74719/#comment181322_74719
The program is an arbitrary list of these four ASCII emoticons, either space or newline separated:
>_> <_< >_< <_>
Pairs of emoticons are taken and parsed into instructions shown below. There may be an odd number of emoticons, see Nested Structures.
>_< >_< - input an integer into the stack
<_> <_> - pop the top of stack and output an integer
The top of stack is implicitly output when the program ends.
>_> <_< - push a 0 into the stack
<_< >_> - DROP the top of stack
>_> >_> - increment the top of stack
<_< <_< - decrement the top of stack
>_< <_< - add the top of stack and second-to-top of stack
>_< >_> - subtract from the top of stack the second-to-top of stack
<_> <_< - multiply the top of stack and second-to-top of stack
<_> >_> - divmod - divide the top of stack by second-to-top of stack, push the quotient and remainder (quotient to top of stack)
>_> >_< - DUP - push a copy of the top of stack (1 2 ==> 1 2 2)
>_> <_> - SWAP - swap the top of stack and second-to-top of stack (1 2 3 ==> 1 3 2)
<_< >_< - ROLL - roll the stack upward (1 2 3 4 ==> 4 1 2 3)
<_< <_> - PICK - push a copy of the second-to-top of stack (1 2 ==> 1 2 1)
<_> >_< - start a nested structure
>_< <_> - end a nested structure
The sole shifty-eyes emoticon right after the end of the nested structure will determine which type the structure was.
>_> or >_< - if: the nested structure runs if and only if the top of stack is nonzero
<_< or <_> - while: the nested structure runs while the top of stack is nonzero
Count down from n to 1:
>_< >_< <_> >_< >_> >_< <_> <_> <_< <_< >_< <_> <_<
Explanation:
>_< >_< - input
<_> >_< - start n.s.
>_> >_< - dup
<_> <_> - output
<_< <_< - decrement
>_< <_> - end n.s.
<_< - n.s. was while