The generator matrix

 1  0  1  1  1  6  1  1  0  1  1  6  1  2  1  1  1  2  1  1  1
 0  1  3  6  5  1  0  3  1  6  5  1  0  4  2  4  2  6  7  1  0
 0  0  4  0  4  0  0  4  0  0  4  0  4  4  4  0  0  4  0  4  0
 0  0  0  4  4  4  4  4  4  0  0  0  4  0  0  0  4  4  4  0  0

generates a code of length 21 over Z8 who´s minimum homogenous weight is 18.

Homogenous weight enumerator: w(x)=1x^0+7x^18+58x^19+35x^20+86x^21+7x^22+38x^23+9x^24+10x^25+1x^26+2x^28+1x^30+1x^36

The gray image is a code over GF(2) with n=84, k=8 and d=36.
This code was found by Heurico 1.16 in 0.00227 seconds.