I can scratch this one off the 'to do' list, adding a blank tie tack/lapel/hat pin to a Sailor's Cross Knot, giving it another way to be worn/carried besides as a lanyard/fob/keychain pendant.
The orange one was tied and tightened with 1.4mm cord, then super glued to one pin, since that's the adhesive I had handy. The blue cross was loosely tied, just enough so I could insert a blank pin inside the knot, and then tightened up around the pin.
I gave Ma first choice of the two I tied and she picked the blue one, so Pa got the orange. I don't know how well the super glued one will stay attached to the smooth flat surface of the pin or if another adhesive might work better, but I reckon Pa will let me know if it up and disappears on him, lol.
The blue one may have issues with securing it through thicker garments/material, since you lose some of the pin length with the cord tied around the backside, so there is a possible tradeoff on that.
The Frayed Knot Arts website has a nice example of a mini star knot tied around a longer style button hole lapel pin.