The generator matrix

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

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

Homogenous weight enumerator: w(x)=1x^0+135x^18+114x^19+278x^20+64x^21+230x^22+52x^23+73x^24+16x^25+51x^26+10x^27

The gray image is a code over GF(2) with n=84, k=10 and d=36.
This code was found by Heurico 1.11 in 0.00697 seconds.