The generator matrix

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

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

Homogenous weight enumerator: w(x)=1x^0+55x^12+146x^13+258x^14+476x^15+664x^16+920x^17+1265x^18+1548x^19+1786x^20+1944x^21+1936x^22+1636x^23+1328x^24+964x^25+582x^26+420x^27+247x^28+118x^29+54x^30+16x^31+15x^32+4x^33+1x^34

The gray image is a code over GF(2) with n=42, k=14 and d=12.
This code was found by Heurico 1.16 in 7.39 seconds.