For reasons not relevant here, after Having Been Advised to not walk barefoot on our wood floors, I picked up a pair of beach / pool sandals with comfy soles. Although they have a white logo, they’re black and essentially invisible in the dark when I need them most.
Start by taking a photo of the logo on the clamped-flat upper strap:

Use GIMP to select the white area, clean it up a little, convert the selection into a path, export it as an SVG file, import into LightBurn, scale to match reality, and Fire The Laser:

That’s a roll of glow-in-the-dark tape which is almost certainly a lethal combination of PVC and phosphorescent stuff, so hold your breath while it cuts.
It’s “actually a “kiss cut” through the tape, but not through the backing paper, letting the whole thing hang together after the operation.
Peel-n-stick on the (still flattened) sandals, expose them to light, and It Just Works:

The fit isn’t perfect, perhaps due to insufficient flattening, but it’s close enough for my simple needs.
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