(common this is a riddle) To the sight, I may be plain
Or I may cause you to rack your brain
My makeup is not without rhyme or reason
But finding me might give your brain some teasin'
It would not be unusual at all
To find me on a surface, like a wall
I suggest that you follow me
To have that dress made properly
It's not me if there is no repeating
Now tell me what I am, without cheating

What is the answer?