Looking at your screenshot, why are the numbers at top left zero not -160?
I just moved its offset to null because if there was a mirroring problem it would be there.
But even with the - 160 value I got no mirror effect.
That logic doesnât seem right though! 
If thereâs mirroring and you move the offset to zero, then the mirroring is off to the left.
Just tried this example and do see the mirroring,but not bang in the middle. The sketch seems to be dependent on screen size and the zero line is in the wrong place?
If there is a mirroring, it occurs between positive values and negative ones if I got @imaginativeCODE correctly. So noise(1) would give the same result as noise(-1).
In his example you start with an offset of - 160 so the mirror is far to the right. Thatâs why I put no offset to recenter everything and see if I could see the mirror effect.
Now with what you just said there might actually be a problem in the way the curves are displayed and that is making the three of us see 3 different behaviors.
You have to start with a negative offset to get zero in the middle of the screen! Iâd take a bet their screen is 1600px wide (160 * 2 * 5). Mine is 1920px (so 192 * 2 * 5). And sure enough if the offset is -192 it mirrors in the middle. Good reason to make all values relative to width!
Hooo I get it nowâŚ
I thought it was always centered on the offset value, I didnât pay too much attention to the way it was coded actually.
I now found the symmetry 
But giving it an offset actually works @imaginativeCODE. If you know what will your minimum be, then you can offset it by that minimum and you wonât have that symmetry. It will still exist but not in the range you will use.
Yeah thatâs what i was trying to point out but like you said I think I have smaller screen. Having the a high offset
number you would have to hold the button down forever before seeing the mirror effect. Aka offset like 10,000.