The generator matrix

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

generates a code of length 6 over GR(16,4) who´s minimum homogenous weight is 8.

Homogenous weight enumerator: w(x)=1x^0+18x^8+240x^9+144x^10+804x^12+1392x^13+1008x^14+5376x^15+5817x^16+3408x^17+17520x^18+16128x^19+8148x^20+4176x^21+1296x^22+60x^24

The gray image is a code over GF(4) with n=24, k=8 and d=8.
This code was found by Heurico 1.16 in 0.328 seconds.