Toroidal chaos is quite rare in 3D autonomous continuous systems. Apart the toroidal system produced by Otto Rössler in 1979 but which does not produce chaotic behaviors, the system by Bo Deng could be one of the very first to produce toroidal chaos. What is quite interesting in this attractor is that there is a unique folding mechanism : this is thus unimodal chaos.
This is a set of three ordinary differential equations reading as 
This system produces a toroidal chaotic attractor (Fig.1) with parameter values as a=3, b=0.8, c=1, d=0.1, m=0.05, , R=10, , , , and . A sketch of the attractor is shown in Fig. 2.
A Poincaré section revealing the single folding is shown in Fig. 3.
 Bo Deng, Constructing homoclinic orbits and chaotic attractors, International Journal of Bifurcation & Chaos, 4, 823-841, 1994.