The generator matrix

 1  0  1  1  1  1  1  0  1  1  1  1
 0  1  1  2  0 2X+1  2  1  0  X 2X  0
 0  0 2X  0  X 2X  X  0 2X  X  0  0
 0  0  0  X  X 2X 2X  X  0  0 2X  0

generates a code of length 12 over Z3[X]/(X^2) who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+44x^18+54x^20+50x^21+216x^23+50x^24+216x^26+54x^27+40x^30+4x^33

The gray image is a linear code over GF(3) with n=36, k=6 and d=18.
This code was found by Heurico 1.16 in 0.00117 seconds.