  Relational particle mechanics are models in which there is, overall, no time,
position, orientation (nor, sometimes, scale). They are useful for
whole-universe modelling - the setting for quantum cosmology. This note
concerns 3 particles in 1d in shape-scale split variables. The scale part
parallels certain Friedmann equations, while in this note the shape part
involves functions on the circle. The scale part is taken to be `heavy' and
`slow' so the semiclassical approach applies and scale provides an approximate
timestandard with repect to which the light physics runs. Relational particle
mechanics moreover provide conceptual models of inhomogeneity, structure
formation and nontrivial linear constraints (minisuperspace models do not and
midisuperspace models only do at the cost of substantial complications).
