Charting Patterns for Duplicate Stitch - How?

My granddaughters requested new hats this year (they’ve outgrown the ones I made last year) so I’ve run up a couple of them. Now I’d like to “duplicate stitch” something on the hats in a glow-in-the-dark yarn …maybe hearts, stars, or flowers. I think I understand how duplicate stitch works but I just cannot come up with a pattern to use for any of the items I would like to add to their hats.

I don’t want anything complicated. Just a simple heart or a five point star or five petal flower that I can add to the hat on the stockinette, after the ribbing and before the decreases start. I’ve figured out that the hat is 140 stitches in circumference and there are 15 rows of stitches between the ribbing and the decreases. I’d like to put about 6 repeats of the pattern around the hat, which would (I think) mean that each repeat would be a maximum of 21 stitches wide and 15 rows tall which would leave 2 or 3 stitches between each repeat. But I just can’t seem to make a nice looking pattern that will fit within these parameters. I’m not surprised that I can’t as I’m not very artistic. But my patterns all look very jagged, since you have to use full stitches and can’t use half stitches like you can in cross-stitch patterns.

Anybody have advice or existing patterns they’d like to share?

I did something similar with the Booga bags I made my nieces and nephew. Since I couldn’t find a variegated yarn in the right colours I used solid colour yarn and then duplicate stitched a pattern on each of them (a flower, a butterfly and a spider). You can see them on my Ravelry page (see signature).

The only real advice I can offer you is to find some knitting graph paper. They are a few sites online that offer free graph paper. The one I’ve used is

but you should be able to find other by doing a google search for “knitting graph paper” or something similar.
It took me a while to get the look I wanted.
I started by marking the area that I knew the design had to fit in. In your case 15 sts high and 21 sts wide. I started in the centre and filled in the squares to make the body of the butterfly and when it looked alright I moved on to the wings and so on.

It’s a lot of trial and error but it can be done.

Good Luck!

You might find something already charted at one of these.

You should be able to find something here. Lots if simple charts