Ursi wanted neutral blocks with a 'pop' of colour.
The size she asked for was unusual, 13" unfinished. So that adds up to 12.5" finished size. Which just neatly divides by 5, giving rows and columns of 2.5" each, ( plus seam allowance, 3" each)
So I sat down and watched a bit of television with a notepad on my knee, and scribbled 5 by 5 squares, and doodled in them.
An hour later I had decided to put in some flying geese, and a small square in the centre, to give my pop.
This may be a block someone else has designed previously, but even if it is, I made it up my own self, so it is my block.