How can you code a system? This question has many perspectives depending on what we mean by code and by system. In this talk we will take the perspective of an ergodic theorist and look at encoding of free ergodic probability preserving transformations. A classical result here is due to Krieger who showed that this encoding can be done by bi-infinite sequence of unconstrained symbols from a finite alphabet. In this talk we will be talking about analogous theorems for encodings of Zd actions when these symbols have constraints (for instance when adjacent symbols are distinct or systems arising from tilings) which use some interesting combinatorial estimates of independent interest.