Odds are your shoelace isn't monofilament, since it's almost certainly several strands that have been twisted together into a string or cord. Fishing line is usually monofilament, these days, being made out of synthetic materials like nylon or what have you...
I appreciate the reference to a classic bit of shadowtalk, but I've been wondering for years if it means the future shoelaces of 2050 are actually single stand or if said shadowland commentator or just didn't know what monofilament meant.