Dynamic Time Variant calculations in DAX

A common requirement in any set of calculations is to create a range of time variants on any measure - Prior Period, Year to Date, Prior Year to Date, Prior Quarter. you think of a time slice and someone will find it useful. However the downside to this is that in the model you end up maintaining lots of calculations that are all largely doing the same thing. Any good coder likes to parameterise and make code reusable. So how could we do this in Tabular? There is a way that is a very specific variant of the idea of Parameter Tables