Someone is too likely to burst your I-Invented-a-Crochet-Stitch bubble. To say, "Oh, yeah, my grandmother made me a blankie with that exact same stitch."
Or, "Wasn't that in a summer issue of Interweave Crochet?"
I improvised/made up a stitch pattern recently. I started off a swatch with back-loop ribbing, and I thought, what if I change the single crochet to half double? To double? To treble? To double treble?
Before I knew it, I had a reversible fabric with two distinct sides, both with an architectural vibe. One looked like overlapping pleats; the other had pronounced ridges. Eventually, this made-up stitch became a hat pattern, Lassen.
'My' made-up stitch pattern uses just two basic stitches: double treble and half double crochet. You work in the back loops of the double treble, and the "back-back" loops of the half double. (I blogged about the back-back loops of hdc in July.)
I can see someone somewhere sometime in the distant past working this exact same stitch pattern, making a scarf maybe. Thinking, Ah, look what I came up with . . . .