I like the rich2005 grid (Filters/Render/Pattern/Grid), it's very easy and has a lot of potential later on with with an "Alpha to selection / Select > Feather-grow/shrink-border" and so
Background green (can be a gradient(like below) or pattern or whatever)
New transparent Layer > then Filters/Render/Pattern/Grid
Right click on that layer grig > Alpha to selection then > Select > Border >2 pixels
New layer fill border with red > Layer mode > LCh Lightness (I was just trying different mode)
my two cents
Background green (can be a gradient(like below) or pattern or whatever)
New transparent Layer > then Filters/Render/Pattern/Grid
Right click on that layer grig > Alpha to selection then > Select > Border >2 pixels
New layer fill border with red > Layer mode > LCh Lightness (I was just trying different mode)
my two cents