Haha, yes welcome to my world.
What my intention is to fill the screen randomly but not entirely random.
For every ROW I want ONE tile to be added in a random position on that row.
Repeat down the rows, and then start again from top, until the screen is filled.
That was my intention.
My idea of line 4 btw was to fill it with numbers (01234, 01234.... etc) but it is not needed because it is temp! so, removed.