\[
\boxed{
 \left\{ {\frac {\rm d}{{\rm d}t}}x \left( t \right) =1/2\, \left( x \left( t \right)  \right) ^{2}-1/24\,y \left( t \right) ,{\frac {\rm d}{{\rm d}t}}y \left( t \right) =2\,x \left( t \right) y \left( t \right) -3\,z \left( t \right) ,{\frac {\rm d}{{\rm d}t}}z \left( t \right) =3\,x \left( t \right) z \left( t \right) -1/6\, \left( y \left( t \right)  \right) ^{2} \right\} }
\]