The generator matrix

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

generates a code of length 21 over Z4[X]/(X^3+2,2X) who´s minimum homogenous weight is 15.

Homogenous weight enumerator: w(x)=1x^0+98x^15+815x^16+3204x^17+11317x^18+28452x^19+53377x^20+66940x^21+54292x^22+28770x^23+10926x^24+2916x^25+821x^26+168x^27+33x^28+12x^29+2x^30

The gray image is a code over GF(2) with n=168, k=18 and d=60.
This code was found by Heurico 1.16 in 119 seconds.