The Rössler system is dx/dt = −y − z, dy/dt = x + ay, dz/dt = b + z(x − c), here with a = b = 0.2 and c = 5.8. The orbit spirals out in the xy plane while z stays near zero. Once x passes c, the one nonlinear term zx lifts z sharply, and the −z in dx/dt folds the orbit back