It's impossible to have a lossless compression system that will always compress anything down to less size than it was originally, otherwise you could run it as

It's impossible to have a lossless compression system that will always compress anything down to less size than it was originally, otherwise you could run it as many times as you want and compress everything down to 1 bit. This includes "pointer to pi digits". What would probably happen there is the byte representation of the offset would be longer than the input string itself! Although, now for curiousity, I'd like to actually try that "offset in pi" algorithm. :) Just for fun.