OptionalnrItems: numberOptionalmin: numberOptionalmax: numberOptionalease: easeEnumHow many numbers to produce, including min and max; at least 2.
The first number.
The last number.
The easing curve that spaces the numbers: an easeIn curve bunches them near min, an
easeOut curve near max, an easeInOut curve at both ends.
When true, the result holds the gaps between neighboring numbers instead of the numbers
themselves; the first entry is min.
A start, an end, a count and an easing curve for
vector.spanEaseItems, which spaces the numbers unevenly along the curve.