Figure 1
A changing past. When time t3 is present, a positive retroactive declaration D is made, making entity e having had institutional property Y at time t1 although e did not have this property when t2 was present and t3 was yet to be. The dotted arrow symbolises backward grounding or causation; the blue circle represents the moving, objective Present. A similar figure could be used to illustrate a negative retroactive declaration that makes a past instantiation of some Y-property at t1 disappear (the ‘Y’ symbol would then be placed in the left-hand side of the figure, and only there).
Figure 2
Retroactive mere Cambridge change in B-time. It is always or timelessly the case that ‘Y’ applies to e at t1 because of declaration D at t3.