The generator matrix

 1  1  1  1  1  1  1  1  X  X  X  0  0  0  1  1  1  1  1  1  1
 0  X  0  X  0  0  X  X  0  X  X  X  X  0  0  0  X  X  0  0  X
 0  0  X  X  0  X  X  0  X  X  0  0  X  X  0  X  X  0  0  X  X

generates a code of length 21 over Z2[X]/(X^2) who´s minimum homogenous weight is 21.

Homogenous weight enumerator: w(x)=1x^0+8x^21+3x^22+3x^24+1x^30

The gray image is a linear code over GF(2) with n=42, k=4 and d=21.
This code was found by Heurico 1.16 in 0.00113 seconds.