From wikipedia: Attempting to restrict the distribution of gun plans via the Internet has been likened to the futility of preventing the widespread distribution of DeCSS, which enabled DVD ripping.[168][169][170][171] After the US government had Defense Distributed take down the plans, they were still widely available via the Pirate Bay and other file sharing sites.[172] Downloads of the plans from the UK, Germany, Spain, and Brazil were heavy.[173][174] Some US legislators have proposed regulations on 3D printers to prevent them from being used for printing guns.[175][176] 3D printing advocates have suggested that such regulations would be futile, could cripple the 3D printing industry, and could infringe on free speech rights, with early pioneer of 3D printing Professor Hod Lipson suggesting that gunpowder could be controlled instead.[177][178][179][180][181][182]