The generator matrix

 1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1
 0  4  0  0  0  0  0  0  0  0  0  0  0  0  0  0  0  4  4  4  4  4  4  4  0  0  4  4
 0  0  4  0  0  0  0  0  0  0  0  0  4  0  0  4  4  4  4  0  4  4  4  0  4  4  4  0
 0  0  0  4  0  0  0  0  0  0  0  0  4  4  4  4  4  0  4  4  0  4  0  0  0  4  0  0
 0  0  0  0  4  0  0  0  0  0  0  4  0  4  4  0  4  4  4  0  4  4  0  0  0  0  0  4
 0  0  0  0  0  4  0  0  0  0  0  4  0  0  4  4  4  4  0  0  0  4  0  4  4  4  4  4
 0  0  0  0  0  0  4  0  0  0  4  0  0  0  4  4  0  0  0  4  0  4  4  4  0  4  4  0
 0  0  0  0  0  0  0  4  0  0  4  0  0  4  0  0  4  0  0  0  4  4  4  0  0  4  4  4
 0  0  0  0  0  0  0  0  4  0  4  4  4  4  0  0  0  0  0  4  4  0  4  4  0  4  0  0
 0  0  0  0  0  0  0  0  0  4  4  4  4  0  0  4  4  4  0  0  4  0  0  4  0  0  4  0

generates a code of length 28 over Z8 who´s minimum homogenous weight is 20.

Homogenous weight enumerator: w(x)=1x^0+148x^20+255x^24+3288x^28+255x^32+148x^36+1x^56

The gray image is a code over GF(2) with n=112, k=12 and d=40.
This code was found by Heurico 1.16 in 2.78 seconds.