The generator matrix

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

generates a code of length 18 over Z2[X]/(X^4) who´s minimum homogenous weight is 12.

Homogenous weight enumerator: w(x)=1x^0+24x^12+24x^13+41x^14+80x^15+41x^16+536x^17+564x^18+544x^19+32x^20+72x^21+30x^22+16x^23+30x^24+8x^25+4x^26+1x^30

The gray image is a linear code over GF(2) with n=144, k=11 and d=48.
This code was found by Heurico 1.16 in 0.016 seconds.