Multiple indexes on the same column list

Zohar Elkayam wrote about the new feature added in Oracle 12c that enables creation of multiple indexes on the same column list (as long as they are different somehow [unique vs. non-unique, b*tree vs. bitmap, etc.] and only one of them is visible).

If the same capability is needed in pre-12c versions: create the new index with the addition of an extra column containing a constant. For example, if the original index is based on (X, Y), then the new index can be based on (X, Y, 1).