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  1  1  1  4  2  1  1  2  0  1  1  1  1  1  0  1  2  0  2  1  1  2  2  1  1  0  0  2  1  1  1  0  0  2  2  2
 0  2  0  0  0  2  6  2  0  0  4  4  2  2  6  2  0  4  2  2  6  4  2  0  0  4  6  4  2  2  6  2  2  2  6  2  4  4  0  2  2  4  0  6  0  0  0  6  4  0  6  0  4  2  2  0  4  6  2  2  0  2  0  0
 0  0  2  0  2  2  6  0  0  4  2  2  2  6  4  0  0  0  6  0  4  2  2  2  6  6  2  0  0  4  6  6  2  2  2  0  4  4  0  4  4  0  4  6  2  2  6  6  0  0  4  4  2  2  0  2  2  2  0  6  2  0  4  4
 0  0  0  2  2  0  6  2  4  2  2  0  0  2  0  6  4  2  0  4  6  6  6  4  6  0  4  0  2  0  2  4  0  2  2  6  2  2  0  2  6  2  2  6  6  4  4  0  2  6  4  0  4  2  4  0  2  6  6  2  4  2  6  2
 0  0  0  0  4  0  0  0  0  0  0  4  4  4  0  0  4  0  0  0  4  4  4  0  0  4  4  4  4  4  0  4  4  0  4  4  0  4  4  0  4  4  0  0  4  4  0  0  4  4  0  0  0  4  4  4  4  4  0  4  4  4  0  4
 0  0  0  0  0  4  0  4  4  0  4  4  4  0  4  0  4  4  0  0  0  0  0  4  0  4  4  0  0  0  4  0  4  4  4  0  0  0  4  4  4  4  0  0  4  0  4  4  4  0  4  4  4  0  0  0  4  0  0  4  4  4  4  0
 0  0  0  0  0  0  4  4  0  4  4  0  4  4  4  4  4  4  4  4  4  4  0  4  0  4  0  0  0  0  0  0  0  4  0  4  4  0  0  0  0  4  4  0  0  0  4  4  0  0  4  4  0  0  0  4  4  0  0  0  4  0  0  0

generates a code of length 64 over Z8 who´s minimum homogenous weight is 56.

Homogenous weight enumerator: w(x)=1x^0+159x^56+16x^57+316x^58+76x^59+438x^60+204x^61+390x^62+252x^63+610x^64+188x^65+336x^66+164x^67+382x^68+100x^69+212x^70+20x^71+97x^72+4x^73+68x^74+35x^76+22x^78+5x^80+1x^92

The gray image is a code over GF(2) with n=256, k=12 and d=112.
This code was found by Heurico 1.16 in 3.22 seconds.