The modified hyperchaotic Rössler system 
was proposed to ensure its synchronization using a single variable. It corresponds to the original hyperchaotic Rössler system  rewritten replacing (x,y,z,w) with (x,y,z,v=y+w). This four dimensional system produces a hyperchaotic attractor (Fig. 1).
This four dimensional system was numerically integrated to produce a data set corresponding to the attractor shown in Fig. 1. There are four columns associated with the time evolution of x, y, z, and v, respectively. Parameter values were b=3 and c=0.05. The sampling time was s. Initial conditions were , , , and .
The observability coefficients for this four dimensional system are , , , , that is, the dynamical variables can be ranked as
 A. Tamasevicius & A. Cenys, Synchronizing hyperchaos with a single variable, Physical Review E, 55, 297, 1997.
 O. E. Rössler, An equation for hyperchaos, Physics Letters A, 71, 155, 1979.