I have a notebook that I carry with me everywhere made by zequenz https://www.zequenz.com/product/zequenz-signature-classic/?attribute_pa_size=a7&attribute_pa_

I have a notebook that I carry with me everywhere made by zequenz https://www.zequenz.com/product/zequenz-signature-classic/?attribute_pa_size=a7&attribute_pa_color=red&attribute_pa_sheet-style=blank https://www.zequenz.com/product/zequenz-signature-classic/?a... It's gridded, it's small, it's also indestructible except for fluids, like you can bend it any way you want, and the paper is really nice to write on. I get them embossed with book <number>. Currently I'm on book 4. Anyways this is where all my ideas go and then I colour code them, sometimes, using the different pens I find in my bag. But I find a notebook to be better than any other tool on the market today for storing, iterating, and processing large conceptual ideas I have about things I want to do.