An example of a code that is neither p-code or s-code but is uniquely decodable? As the title says, code can't be a prefix-code and can't be a suffix-code, but it must be uniquely decodable. One possible code is this: {1, 101, 1001, ... }. Number of zeroes corresponds to the index of the letter in a given alphabet (starting from 0). Clearly it's not p-code and not a s-code and it's uniquely decodable. But I need to find another example of such code. And no, I wont accept {0, 010, 0110, ...}. By the way, code words must consist of 0 and 1, i.e. be binary.
An easy way to get new codes of any size is to compose a prefix non-suffix code and a suffix non-prefix code. For instance, start with the prefix non-suffix code $X_5 = \{0, 10, 110, 1110, 1111\}$ and compose it with the suffix non-prefix code $\{0,01\}$, which consists to replace $1$ by $01$ in $X_5$ to get
$$
S_5=  \{0, 010, 01010, 0101010, 01010101\}.
$$
The resulting set is a code that is neither prefix nor suffix. 

N.B. The advantage of this method is that you always get codes, no verification needed.