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  2  1  1  1  1  1  1  1  1  1  2  1  1  1  1  1  2  1  1  1  2  1  1  1  1  4  1  1  1  2  1  1  2  1  2  1  2  8  1  8  1  4  0  4  4
 0 12  0  0  0  0  0  0  0  4 12 12  4 12  4 12  8 12  8 12  0  8 12  8  4 12 12  8  4  4 12  0  8 12  0  8  8  8  0  4  0 12  0  4  8  4  4  0  4  0 12 12 12  4 12  4  0  8  0 12  4  4  8  4  0  0  8  8  4  0 12
 0  0 12  0  0  8 12 12  4  4  4  8  4 12  0  8  0  8  0  4  4  4  4  4 12  0  8 12 12  0  8  8 12  0  0  8  8 12  0  0  8  4  0  0  8  4  8 12  4  8  8  4  8 12 12  8 12  0 12  4 12  8  0 12  8  0 12  0  0  0  4
 0  0  0 12  0 12 12  4  8  0  0  0  4 12  4  4  8 12  4  4  8  8  4  4  0  8  0  4  0  8  4  4 12  0  0  8  4 12  4 12  0  0  8  4  4  0  0 12 12  4  8  8  4  0  8  8  4  8  8 12  4  4  4 12 12  4 12  4  0 12  0
 0  0  0  0 12  4  8  4  4  0  4  4  4  0  8 12 12  8  8  4  8 12  0 12  4 12  8  0  0  0  4  4  8  4  8  0 12 12 12 12 12  0  4 12  8  4  4  0  8  0  0  4  0 12  8  4  0  8  8  0 12  0  0 12 12 12  0  8  0  8 12

generates a code of length 71 over Z16 who´s minimum homogenous weight is 64.

Homogenous weight enumerator: w(x)=1x^0+123x^64+16x^65+218x^66+76x^67+372x^68+420x^69+616x^70+552x^71+626x^72+360x^73+314x^74+76x^75+125x^76+36x^77+60x^78+48x^80+40x^82+13x^84+1x^88+2x^92+1x^112

The gray image is a code over GF(2) with n=568, k=12 and d=256.
This code was found by Heurico 1.16 in 0.759 seconds.