I think this way only the same two Segments will be added and removed, since you remove the Segment with index 1 and you readd the spare segment to the wheel with the lowest free index, so 1.

I suppose Spare Segments needs not to be “primed”. It’s sufficient that are an ordered list, when new spare segments are added at the bottom and segments that must be readded to the Wheel are taken from the top. A FIFO list :)

About Indexes, I suppose they must be updated accordingly to the current position of the Segments in the Wheel list and than Spare segments can be readded at the bottom of the list.

[Marco Sulla] That shouldn’t occur because the indices will be renumbered in between, so the lowest available number will be much higher than 1. This results from the second paragraph of “The Wheel”, which includes:
“If a Segment on the wheel has Index N where N is greater than 1, and there is no Segment with Index N-1, the Index of that Segment becomes N-1. If two Segments on the wheel have the same Index, the Index of the Segment whose Name is Alphabetically later is Increased by 1.”

You said well, “where N is greater than 1”...
Unluckily, I have to vote against.

CoV

Mmmmhhhh…. sorry for the confusion :( I asked for clarifications on Slack and it seems that the change of the Indexes should be applied immediately, so there’s no way that the Index number 1 will remain vacant before any Spare segment is readded to the Wheel.