okay, so the toys are technically not that complex, but manufacturing a toy that a complex animal will be intent on murdering is not as easy as it sounds.  hours of r&d, testing and experimenting go into each toy.  felines prefer products that are natural and mimic nature - ours do that.  how can we keep the string from tangling and twisting up into knots?  how many swivel points are needed to never have to worry about tangles?  what type of swivel spins the best?  is bamboo strong enough for rough play?  what is the safest type of string/cordage to use?  how do you build in fail-safe mechanisms?  how do we make the toy as safe as possible?  are natural products just as strong as synthetic ones?  all of these questions and more were answered and solved.  we are kind of nerdy when it comes to this stuff but that's okay because we know that you and your cat will love our toys.