The generator matrix

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

generates a code of length 21 over Z4[X]/(X^2+2X+2) who´s minimum homogenous weight is 17.

Homogenous weight enumerator: w(x)=1x^0+140x^17+228x^18+472x^19+679x^20+1076x^21+666x^22+504x^23+195x^24+92x^25+16x^26+16x^27+5x^28+4x^29+2x^30

The gray image is a code over GF(2) with n=168, k=12 and d=68.
This code was found by Heurico 1.16 in 2.09 seconds.