The generator matrix

 1  0  1  1  1  1  1  1  1  0  1  1  0  1  1
 0  1  1  a 3a+3  0 2a+3  a a+1  1 a+1 2a+3  1 2a+3  0
 0  0 2a+2  0  0  0  0  2  2  2  2  2 2a+2  0  0
 0  0  0  2  0  0  2 2a+2  0 2a+2 2a 2a 2a+2  2  0
 0  0  0  0 2a+2  0 2a  0 2a 2a  2 2a 2a+2 2a  2
 0  0  0  0  0  2 2a 2a 2a+2 2a+2 2a+2  2  2  2 2a+2

generates a code of length 15 over GR(16,4) who´s minimum homogenous weight is 28.

Homogenous weight enumerator: w(x)=1x^0+42x^28+228x^32+48x^33+966x^36+576x^37+768x^39+5769x^40+2592x^41+4608x^43+16476x^44+5184x^45+6912x^47+16539x^48+3888x^49+606x^52+279x^56+54x^60

The gray image is a code over GF(4) with n=60, k=8 and d=28.
This code was found by Heurico 1.16 in 2.18 seconds.