The generator matrix

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

generates a code of length 21 over Z4 who´s minimum homogenous weight is 12.

Homogenous weight enumerator: w(x)=1x^0+310x^12+672x^14+2970x^16+4032x^18+9606x^20+5376x^22+6552x^24+2112x^26+962x^28+96x^30+77x^32+2x^36

The gray image is a code over GF(2) with n=42, k=15 and d=12.
This code was found by Heurico 1.16 in 10.1 seconds.