These don’t seem like very complex optical illusions, unless my eyes are really getting bad 🙂
I would guess that the first is just an image of Johnny Depp in a light gray with a line pattern overlaid.
You can achieve something like the second example if you create a repeating pattern of circles (use Edit > Define Pattern or download one), then type your text in a layer above that in Black and set it to the Soft Light blend mode.
Darby Edelen