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  2  2  2  2  1
 0  2  0  0  0  0  0  0  0  0  0  2  0  0  2  2  0  0  0  0  2  2  2  2  2  2  0  0
 0  0  2  0  0  0  0  0  0  0  0  2  2  2  2  2  0  0  0  2  2  0  0  2  0  0  2  0
 0  0  0  2  0  0  0  0  0  0  2  0  2  2  0  2  2  0  2  0  2  2  2  0  2  2  0  0
 0  0  0  0  2  0  0  0  0  0  2  0  0  2  2  2  2  2  0  2  0  0  0  0  0  2  2  0
 0  0  0  0  0  2  0  0  0  2  0  0  0  2  2  0  2  0  2  2  2  0  0  2  2  2  2  0
 0  0  0  0  0  0  2  0  0  2  0  0  2  0  0  2  2  2  0  2  2  0  2  2  2  0  2  0
 0  0  0  0  0  0  0  2  0  2  2  2  2  0  0  0  0  0  2  2  2  2  2  2  0  2  0  0
 0  0  0  0  0  0  0  0  2  2  2  2  0  0  2  2  2  0  0  0  2  0  0  0  0  0  2  2

generates a code of length 28 over Z4 who´s minimum homogenous weight is 20.

Homogenous weight enumerator: w(x)=1x^0+65x^20+186x^24+128x^26+282x^28+128x^30+156x^32+69x^36+8x^40+1x^48

The gray image is a code over GF(2) with n=56, k=10 and d=20.
This code was found by Heurico 1.16 in 0.0635 seconds.