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

generates a code of length 75 over GR(16,4) who´s minimum homogenous weight is 212.

Homogenous weight enumerator: w(x)=1x^0+177x^212+12x^213+273x^216+144x^217+96x^220+648x^221+15x^224+1296x^225+177x^228+972x^229+108x^232+30x^236+57x^244+42x^248+9x^252+21x^260+6x^264+6x^268+3x^280+3x^284

The gray image is a code over GF(4) with n=300, k=6 and d=212.
This code was found by Heurico 1.16 in 44.6 seconds.