gathering vapors, dispersing precipitates

now/never
/                               \
actual                                    impossible
potential                                    possible
|                                         |
past\future   __   probable/improbable

…

now                    /                   never
/\                                              /\
potential/actual                                im-/possible
/\                                                              /\
past/future                                                  im-/probable

…

Enthymeme – Wikipedia, the free encyclopedia.