The generator matrix

 1  0  1  1  1  1  1  1  1  1  1  1
 0  1  1 31 16 48  4 19  0 36 31 16
 0  0 35  0 35  7 35  7 42 14  7 42
 0  0  0  7 28 28 21 42  0 42  7 42

generates a code of length 12 over Z49 who´s minimum homogenous weight is 56.

Homogenous weight enumerator: w(x)=1x^0+210x^56+1176x^60+480x^63+8232x^66+14112x^67+468x^70+49392x^73+42336x^74+888x^77+354x^84

The gray image is a code over GF(7) with n=84, k=6 and d=56.
This code was found by Heurico 1.16 in 0.586 seconds.