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  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  1  4  1  1  1  1  1  1  1  1  0  1  1  1  1  1  1  1
 0  2 12  6  0  6 12 10  0 10 12  6  0  6 12 10  8 14  4 10  0 12  6 10  8 14 12 10 14  0  2  4 14  0  8  8  0  6  6  6  6 10  2 12  4  8  0 12 10  0  0 12 14  6 14  8  4  6  2  8  0 14  0 12
 0  0  8  0  0  0  0  0  0  0  8  0  8  0  8  0  8  0  0  0  8  0  8  8  0  8  8  8  8  0  0  0  8  8  8  8  0  8  8  0  0  0  0  0  0  8  8  0  8  0  0  8  8  8  8  8  0  8  8  8  8  8  8  8
 0  0  0  8  0  0  0  0  0  0  0  8  8  8  8  8  8  0  8  8  8  0  8  0  0  8  8  0  8  0  8  8  0  0  0  0  8  0  8  8  0  8  0  8  8  0  8  0  0  8  0  0  0  8  0  8  0  8  8  8  0  8  8  8
 0  0  0  0  8  0  0  0  8  0  0  0  8  8  8  8  0  8  8  8  0  8  0  8  0  8  0  8  0  8  8  8  0  8  0  8  0  8  0  0  8  0  8  8  8  0  8  0  0  0  0  8  0  0  8  8  0  8  8  0  8  8  8  8
 0  0  0  0  0  8  0  0  0  8  0  0  8  8  8  8  8  0  8  0  0  8  8  8  8  0  0  8  8  8  0  8  0  8  8  8  8  0  0  8  8  8  8  0  0  8  0  0  8  0  8  0  0  0  0  0  0  8  8  8  0  8  8  0
 0  0  0  0  0  0  8  8  8  8  8  8  0  8  8  0  0  0  0  8  0  0  8  0  8  0  8  8  0  8  0  8  8  8  0  0  0  8  8  0  0  8  8  8  0  8  0  0  0  0  0  8  0  0  0  8  0  8  0  8  0  8  8  8

generates a code of length 64 over Z16 who´s minimum homogenous weight is 58.

Homogenous weight enumerator: w(x)=1x^0+184x^58+223x^60+320x^62+1024x^63+719x^64+1024x^65+192x^66+192x^68+160x^70+16x^72+40x^74+1x^124

The gray image is a code over GF(2) with n=512, k=12 and d=232.
This code was found by Heurico 1.16 in 9.33 seconds.