The generator matrix

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

generates a code of length 21 over Z4[X]/(X^2+2,2X) who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+30x^18+120x^19+116x^20+64x^21+71x^22+36x^23+23x^24+24x^25+10x^26+12x^27+4x^28+1x^30

The gray image is a code over GF(2) with n=84, k=9 and d=36.
This code was found by Heurico 1.13 in 4.2e-008 seconds.