Combine Multiple Columns to One Column in Calc

My data looks a bit like this:

Day 1	Day 2	Day 3
wagons	traders	movie
names	island	games
travel	names	computers
island	wagons
movie		
beaches		

I would like to easily and/or automatically be able to have this data appear in another column as:

wagons	
names		
travel		
island	
movie		
beaches
traders
island
names
wagons
movie
games
computers

That is, I don’t want to have to cut & paste them manually, and I want it to have duplicates if there are duplicates, and to skip blank cells.

Ideally, it would be cool if I could edit the first column set, and have the third (combined) column update to reflect any edits to those source columns.

Check this answer on Stack Overflow. It looks disturbingly complicated.