The generator matrix

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

generates a code of length 21 over Z4[X]/(X^2+2,2X) who´s minimum homogenous weight is 17.

Homogenous weight enumerator: w(x)=1x^0+242x^17+382x^18+532x^19+592x^20+628x^21+610x^22+552x^23+273x^24+202x^25+54x^26+20x^27+6x^28+2x^30

The gray image is a code over GF(2) with n=84, k=12 and d=34.
This code was found by Heurico 1.16 in 15.2 seconds.