It is confusing and error prone therefore knowing that a linear chart
of redshfit observation vs distance(hubble) represents a fixed
expansion rate of space.

And knowing that instead if both curved ends (past & present ends) are
below the linear then it represents an accelerating expansion rate.

(linear means a chart with a linear straight slope increasing
gradually as it is plotted from present to past distances)

As above but instead:

1. What would a decelerating chart of the expansion rate look like?

2. What if the past distance is curved above the linear and the
present distance is curved below the linear?

3. What if both past and present are curved above the linear?

4. What if past is curved below and present curved above?