I keep a stack of plain white index cards around for scribbling on. I've got no talent for reproducing recognizable form, but no-consequence doodling is a great way to come up with ideas when I'm blocked. (It's probably why I usually do my rough drafts in fountain pen - there's something about moving the hand around.)
I really like your patterns. They remind me of a formal garden.
Index cards are a great idea, as I've been known to rip out pages from my sketchbook! No need for that with separate cards.
Now you've mentioned garden, I do see how it could kind of be an aerial view of a garden design :-)