with t as(select 1col1, 2 col2, 3 col3, 4 col4 from dual)
select * from 
 ( Select col1, col2, col3, col4
        , col1+col2 col12, col3+col4 col34 
        , col1+col3 col13, col2+col4 col24 
     from t)
unpivot ((c1,c2) for colsort in (
  (col1, col2) as 1,
  (col3, col4) as 3,
  (col12, col34) as 2,
  (col13, col24) as 2.1
))
;