If I were to take your sample data and create a table with it, I could then list this table and there is no guarantee that the rows would occur in the same order, so you need to provide some criteria on how we determine which two rows to combine to produce the new output. As it is, there is no way to ensure that this table will list as contained in your post unless we just assume we're going to get lucky.

What you could do is also include as the very first column an explicit integer ordering of your data, or some other value that we could sort by.