

there’s a mask process in qr code generation. the masks aims to try to make it look like uniform noise, so you don’t end up with blocks/lines of pure white or pure black. so you won’t end up with any recognizable symbol in the usual algorithmic generation
some more detail: it will use one of these patterns to invert some pixels until it finds one that results in more or less uniform noise.
it will also add a set of pixels in a designated mask identification zone that instructs the decoder which mask was used
















you can if it’s small and in the middle