The generator matrix

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

generates a code of length 21 over Z4[X]/(X^3+2,2X) 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 0.25 seconds.