The generator matrix

 1  0  1  1  1 X+2  1  1  0  1  1 X+2  1  1  0  1 X+2  1  0  1  0
 0  1 X+1 X+2  1  1  0 X+1  1 X+2  3  1  0 X+1  1  3  1 X+1  1 X+1  1
 0  0  2  0  0  0  0  0  0  0  0  0  0  2  2  2  2  2  2  0  2
 0  0  0  2  0  0  0  0  0  0  2  2  2  2  2  0  2  0  2  0  0
 0  0  0  0  2  0  0  0  0  2  2  2  0  0  0  0  2  2  2  2  2
 0  0  0  0  0  2  0  0  2  2  0  2  0  0  2  2  2  0  2  2  0
 0  0  0  0  0  0  2  0  2  0  0  2  2  2  2  2  0  0  0  0  2
 0  0  0  0  0  0  0  2  2  2  2  0  0  2  2  0  0  0  2  2  2

generates a code of length 21 over Z4[X]/(X^2+2,2X) who´s minimum homogenous weight is 15.

Homogenous weight enumerator: w(x)=1x^0+32x^15+98x^16+480x^18+352x^19+960x^20+256x^21+960x^22+352x^23+472x^24+96x^26+32x^27+5x^32

The gray image is a code over GF(2) with n=84, k=12 and d=30.
This code was found by Heurico 1.16 in 31.9 seconds.