The generator matrix

 1  0  1  1  1 3X+2  1  1  2  1  1 3X  1  1  0  1  1 3X+2  X  X  1
 0  1 X+1 3X+2 2X+3  1  2 X+3  1 3X 2X+1  1  0 X+1  1 3X+2 2X+3  1  0 3X+2 2X
 0  0 2X  0 2X  0  0 2X  0  0 2X  0 2X  0 2X 2X  0 2X 2X 2X 2X
 0  0  0 2X 2X 2X 2X 2X 2X  0  0  0 2X  0  0 2X  0  0  0 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+28x^18+164x^19+195x^20+268x^21+192x^22+124x^23+27x^24+20x^25+4x^26+1x^28

The gray image is a code over GF(2) with n=168, k=10 and d=72.
This code was found by Heurico 1.16 in 6.87e-008 seconds.