The generator matrix

 1  1  1  1  1  1  1  1  2  2  2  2  2  2  2  2  1  1  1  1
 0  4  0  0  0  4  4  4  0  0  4  4  0  4  4  0  0  0  0  4
 0  0  4  0  4  4  4  0  0  4  4  0  4  4  0  0  0  0  4  4
 0  0  0  4  4  0  4  4  4  4  0  0  0  4  4  0  0  4  4  0

generates a code of length 20 over Z8 who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+4x^18+52x^20+4x^22+1x^24+2x^28

The gray image is a code over GF(2) with n=80, k=6 and d=36.
This code was found by Heurico 1.16 in 0.00174 seconds.