The generator matrix

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

generates a code of length 21 over Z4[X]/(X^2+2) who´s minimum homogenous weight is 16.

Homogenous weight enumerator: w(x)=1x^0+389x^16+1708x^17+5967x^18+13658x^19+26576x^20+33842x^21+27676x^22+13588x^23+5508x^24+1664x^25+436x^26+50x^27+4x^28+2x^29+2x^32+1x^34

The gray image is a code over GF(2) with n=168, k=17 and d=64.
This code was found by Heurico 1.16 in 33.9 seconds.