I am sure we all investigated this problem at some point, I always thought that two constrictor knots would be the best rope handcuff, but in fact the problem is that the only way to handcuff with rope is to have so much tension that bloodflow would be shut off. Even since ancient times, metal handcuffs or manacles have been used in preference to rope. In modern times, nylon cableties are used as handcuffs when metal ones are not suitable. The s&m bondage scene does utilise an effective wrist binding involving multiple turns around the wrists with frapping turns between the wrists, similar to a shear lashing, but this requires so much cooperation from the bound person, that I regard it as decorative, not a real handcuff.