  We demonstrate propagation rules of subsystem code constructions by
extending, shortening and combining given subsystem codes. Given an
$[[n,k,r,d]]_q$ subsystem code, we drive new subsystem codes with parameters
$[[n+1,k,r,\geq d]]_q$, $[[n-1,k+1,r,\geq d-1]]_q$, $[[n,k-1,r+1,d]]_q$. The
interested readers shall consult our companion papers for upper and lower
bounds on subsystem codes parameters, and introduction, trading dimensions,
families, and references on subsystem codes [1][2][3] and references therein.
