y - free ▁ ▁Pro port ional ▁c ake - cut ting ▁ ▁External ▁links ▁▁ ▁Fair ▁Division ▁Calcul ator ▁– ▁an ▁app let ▁for ▁calculating ▁env y - free ▁division ▁for ▁c akes , ▁ch ores , ▁rooms ▁and ▁r ents . ▁ ▁References ▁▁ ▁Category : F air ▁division ▁Category : Rec re ational ▁mathematics ▁Category : Math emat ical ▁problems <0x0A> </s> ▁In ▁electron ics ▁and ▁cha os ▁theory , ▁Ch ua ' s ▁di ode ▁is ▁a ▁type ▁of ▁two - term inal , ▁non linear ▁active ▁res istor ▁which ▁can ▁be ▁described ▁with ▁piece wise - linear ▁equations . ▁▁ ▁It ▁is ▁an ▁essential ▁part ▁of ▁Ch ua ' s ▁circuit , ▁a ▁simple ▁electronic ▁oscill ator ▁circuit ▁which ▁exhib its ▁cha otic ▁oscill ations ▁and ▁is ▁widely ▁used ▁as ▁an ▁example ▁for ▁a ▁cha otic ▁system . ▁▁ ▁It ▁is ▁implemented ▁as ▁a ▁voltage - control led , ▁non linear ▁negative ▁res istor . ▁ ▁The ▁di ode ▁is ▁not ▁sold ▁commer cially , ▁and ▁is ▁usually ▁built ▁from ▁standard ▁circuit ▁components ▁such ▁as ▁di odes , ▁capac itors , ▁resist ors ▁and ▁op - amps . ▁ ▁There ▁are ▁multiple ▁ways ▁to ▁simulate ▁Ch ua ' s ▁di ode ▁using ▁such ▁components . ▁ ▁One ▁standard ▁design ▁is ▁realized ▁by ▁connecting ▁two ▁negative ▁imped ance ▁conver ters ▁in ▁parallel . ▁ ▁A ▁negative ▁imped ance ▁converter ▁( N IC ) ▁is ▁a ▁simple ▁op ▁amp ▁circuit ▁that ▁has ▁negative ▁resistance . ▁▁ ▁Another ▁implementation ▁uses ▁one