From Spread to SpreadOfSpread

How to group items in a spread?

From Element Chat:
@blacktronics
GroupToSpreadOfSpread.vl (12.1 KB)

@woei
Grouping Items In Spread to SpreadOfSpread.vl (11.4 KB)

not sure if performance would be better if current bucket would be stored in another accumulator instead of GetSlice[-1] on every iteration…