The generator matrix

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

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

Homogenous weight enumerator: w(x)=1x^0+163x^18+140x^19+354x^20+764x^21+357x^22+100x^23+125x^24+20x^25+23x^26+1x^38

The gray image is a code over GF(2) with n=168, k=11 and d=72.
This code was found by Heurico 1.16 in 0.235 seconds.