The generator matrix

 1  0  0  0  0  0  1  1  1  1  0  1  1  1  1  2  2  1
 0  1  0  0  0  0  0  0  0  0  2  2  3  1  3  2  1  3
 0  0  1  0  0  0  0  0  3  1  1  2  2  1  1  0  0  2
 0  0  0  1  0  0  2  1  3  0  3  2  3  1  2  0  2  0
 0  0  0  0  1  0  3  1  2  3  3  1  0  3  1  2  2  0
 0  0  0  0  0  1  1  2  3  2  1  2  3  0  1  1  3  0

generates a code of length 18 over Z4 who´s minimum homogenous weight is 12.

Homogenous weight enumerator: w(x)=1x^0+212x^12+468x^14+795x^16+1056x^18+974x^20+420x^22+124x^24+40x^26+6x^28

The gray image is a code over GF(2) with n=36, k=12 and d=12.
This code was found by Heurico 1.16 in 1.57 seconds.