The generator matrix

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

generates a code of length 18 over Z2[X]/(X^3) who´s minimum homogenous weight is 12.

Homogenous weight enumerator: w(x)=1x^0+43x^12+40x^13+105x^14+120x^15+220x^16+352x^17+287x^18+352x^19+225x^20+120x^21+105x^22+40x^23+23x^24+13x^26+2x^30

The gray image is a linear code over GF(2) with n=72, k=11 and d=24.
This code was found by Heurico 1.16 in 0.0401 seconds.